Systems and methods for flood risk assessment

ABSTRACT

In various embodiments, points from flood maps (e.g., geospatial flood risk zoning maps) may be used in generating a flood frequency versus flood elevation curve for reducing the uncertainty in the flood risk assessment. In some embodiments, geospatial flood elevation lines for flood elevation lines at different flood frequency levels may be defined based on elevation datasets where there are inconsistencies between the elevation datasets and flood maps that were generated. The flood frequency versus flood loss curve may be derived based on the computed flood frequency versus flood elevation curve, digital elevation datasets, and collected damage curve. In some embodiments, the flood risk rating may also be derived and a flood risk assessment report may be generated.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of and is based upon and claims thebenefit of priority under 35 U.S.C. §120 for U.S. Ser. No. 13/051,789,filed Mar. 18, 2011, which is a Continuation of U.S. Ser. No.11/974,911, filed Oct. 16, 2007, now U.S. Pat. No. 7,917,292, the entirecontents of which is incorporated herein by reference.

PRIORITY

This application claims benefit of priority of U.S. Provisional PatentApplication Ser. No. 60/852,379 titled “Systems and Methods for FloodRisk Assessment”, filed on Oct. 17, 2006, whose inventor is Wei Du,which is hereby incorporated by reference in its entirety as thoughfully and completely set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to risk assessment and, morespecifically, to flood risk assessment.

2. Description of the Related Art

Worldwide, floods may be the number one cause of losses from naturalevents. Flood risk may be a function of flood hazards (e.g., hurricanesand/or damage to a levee or dam), property exposure to these hazards,and the damage vulnerability of properties during a flood. Comprehensiveflood risk assessment and flood loss mitigation planning may need toaddress these three aspects. In addition, some flood planners mayconsider alternatives for coping with flood hazards including land-useplanning, upstream watershed treatment, flood-proofing buildings,insurance and reinsurance measures, emergency evacuation, and buildinglevees/dams and other structures.

In the United States, floods may account for significant property andbusiness interruption losses affecting thousands of enterprises eachyear, which may cost more in property damages than other naturaldisasters. In 2005, the flooding from Hurricane Katrina alone causedover $40 billion in property damage, led to over 1600 deaths, andaffected over 250,000 businesses according to the United States CensusBureau. Among federal, public, and private measures on flood lossmitigation, insurance and reinsurance may be a key factor in reducingthe financial risk to individuals, enterprises and even whole societies.Mortgage companies, public sector (from the Federal Emergency ManagementAgency (FEMA) to municipalities), capital markets, insurance, andreinsurance companies may need knowledge about frequencies of floods,flood elevations, and frequencies of flood inundation losses atdifferent property locations in order to underwrite sufficient andcomprehensive policies for these properties.

Traditionally flood risk for both residential and commercial propertiesmay have been determined by whether the properties were inside oroutside FEMA special flood hazard areas (SFHAs). Whether the property isinside or outside of an SFHA may have been the principle risk factorconsidered in determining whether to purchase flood insurance. Floodrisks associated with properties within and beyond SFHAs may bedifferent. In an SFHA, properties located near flood sources with lowerelevations may have a higher flood risk than properties near SFHAsboundaries at a higher elevation. Repetitive loss may occur more oftenin properties at lower elevations because the flood frequencies at lowerelevations may be much higher. Beyond the 100 yr flood zone, propertiesmay also suffer flood damage. For example, based on FEMA records, 30% ofclaims were from the outside of 100 yr flood zones.

SUMMARY OF THE INVENTION

In various embodiments, a flood frequency versus flood elevation curvefor a property point may be derived using points of flood elevation forcorresponding flood frequency derived from flood maps (e.g., geospatialflood risk zoning maps). The points may be statistically determinedpoints that are verifiably discrete. The derived flood frequency versusflood elevation curves may be used to reduce the uncertainty in floodrisk assessment (e.g., for insurance companies calculating policypremiums).

In some embodiments, points may be generated using geospatialpoint/line/polygon/surface features (e.g., flood elevation lines) forflood elevations at different flood frequency levels. The geospatialpoint/line/polygon/surface features may be defined and created based onelevation datasets (e.g., digital elevation maps) and flood maps. Thegeospatial point/line/polygon/surface features may be created/redefinedin locations where there previously were inconsistencies between theelevation datasets and the flood maps that were generated, for example,from computer models and field surveys. In some embodiments, theelevation datasets and flood maps may be digital. In some embodiments, amanual method may be used to overlay the flood map with the elevationdatasets (e.g., an elevation map) and flood elevation lines may bedetermined and/or digitized for flood elevations (e.g., determined usinghydraulic modeling). In some embodiments, a flood source line feature(e.g., a waterway centerline or a coastal line) may be used to determineflood elevation lines. In some embodiments, pre-existing flood elevationlines (e.g., base flood elevation lines) may be extended to formadditional flood elevation lines (e.g., for other flood frequencyboundaries). In some embodiments, slopes of new flood elevation linesmay be determined based on slopes of other flood elevation lines. Invarious embodiments, flood elevation lines may thus be created forpoints between or near existing flood elevation lines.

In various embodiments, flood elevation lines and/or flood boundaries(e.g., pre-existing or derived) may be adjusted to improve the accuracyof the derived points. For example, flood elevation lines may beadjusted on top of digital elevation maps to correlate the endpoints ofthe flood elevation line with points on the digital elevation map withsimilar elevations as the elevation associated with the flood elevationline. In some embodiments, other points on the flood elevation linesand/or other points on the flood map may be adjusted using the digitalelevation map. In some embodiments, flood boundaries may also becorrected (e.g., by using the endpoints of corrected flood elevationlines).

In some embodiments, the flood elevation lines (e.g., pre-existingand/or derived) and flood boundary lines may be used to calculate floodfrequency versus flood elevation curves, flood frequency versus damagecurves, and flood risk ratings. In some embodiments, these curves andflood risk ratings may be derived for a specific property, a geocodedpoint location, or a point of interest (POI). For example, base floodrisk ratings may be derived from the computed flood frequency versusflood elevation curve. As another example, flood risk adjustments (riskload) may be made to the base flood risk rating for flood relatedhazards (e.g., hurricanes, landslides, tsunamis, flash flooding, damageto a levee, or damage to a dam).

In some embodiments, a limited number of statistically and geospatiallyknown flood elevations (such as 100-year and 500-year flood elevations)that may have been verified by detailed hydrologic and hydraulic (HH)studies may be used to predict and extrapolate unknown flood elevationsby using accurate digital elevation data, hydrologic methods, and GIS(Geographic Information System) technology at any given geospatiallocation in a flood risk area.

In some embodiments, FEMA's Flood Insurance Rate Maps may have 100-yearflood elevation lines printed on them for some areas. In someembodiments, FEMA maps may have the 500-year flood boundary printed onthem for some areas, but may not have 500-year flood elevation linesprinted on them. In some embodiments, the 100-year and/or 500-year floodelevation lines may be determined or provided from other flood mapsources (e.g., a FEMA Flood Insurance Study (FIS)).

In some embodiments, a property point for analysis may be provided by auser. The property point may correspond to an address, a geocoded point,a point of interest, a building on a property, etc. In some embodiments,the property point may include the address of a targeted portfolio froma mortgage company, public sector entity (e.g., FEMA, municipalities,states, etc.), capital market entity, insurance company, or reinsurancecompany. The property point may be geocoded by the system. For example,an x,y coordinate (such as a latitude/longitude) may be determined forthe property point. In some embodiments, the 100-year base floodelevation and the 500-year flood elevation may be determined for theproperty point. A determination may be made as to whether the propertypoint is within a 100-year flood zone, a 500-year flood zone, orneither. If the property point is within the 100-year flood zone and/orthe 500-year flood zone, the 100-year and 500-year flood elevation linesfor the property point may be determined. If the 100-year base floodelevation lines exist near the property point, the 100-year base floodelevation for the point may be interpolated from the existing 100-yearbase flood elevation lines (e.g., from two adjacent 100-year base floodelevation lines). If the 100-year base flood elevation lines are notprovided near the point, the 100-year base flood elevation lines may becreated near the point and the 100-year base flood elevation line forthe point may be interpolated. If the 500-year flood elevation linesexist near the property point, the 500-year flood elevation for thepoint may be interpolated from the existing 500-year flood elevationlines. If the 500-year flood elevation lines are not provided near thepoint, the 500-year flood elevation lines may be created near the pointand the 500-year flood elevation line for the point may be interpolated.If the property point is outside the 100-year and 500-year floodelevation lines, the 100-year and 500-year flood elevation lines may bedetermined for the point using various methods.

The flood frequency versus elevation curve may then be determined at theproperty point. Using the 100-year and 500-year flood elevation points,a distribution may be calculated which may provide the flood elevationsat other flood frequencies (e.g., 10 year, 50 year, 1000 year, etc.). Aflood frequency curve versus flood loss may be determined for theproperty point using the flood frequency versus elevation curve andadditional data (e.g., provided by the user about the property point).The information may be used to provide a flood risk assessment report tothe user.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present invention may be obtained when thefollowing detailed description is considered in conjunction with thefollowing drawings, in which:

FIG. 1 illustrates an embodiment of a wide area network (“WAN”).

FIG. 2 illustrates an embodiment of computer system that may be suitablefor implementing various embodiments of a system and method for floodrisk assessment.

FIG. 3 illustrates an embodiment of an example flood map.

FIGS. 4 a-b illustrate embodiments of a plot for a flood elevation pointon the example map.

FIG. 4 c illustrates an embodiment of a flood elevation versus floodreturn period for a property point.

FIG. 5 illustrate an embodiment of a method for providing a flood riskassessment for a property point.

FIG. 6 illustrates an embodiment of a method forinterpolating/extrapolating flood elevations for a property point.

FIG. 7 a illustrates a digital elevation base map with a rivercenterline and a 100-year flood boundary with flood elevation lines andelevation labels.

FIG. 7 b illustrates an embodiment of a map used to determine missingflood elevation lines between pre-existing flood elevation lines.

FIGS. 8 a-b illustrate an embodiment of a map and chart used todetermine missing flood elevation lines using gage station data.

FIG. 9 illustrates an embodiment of using raster images to calculateraster surfaces for 100-year and 500-year flood elevations byTriangulated Irregular Network (TIN) methods using flood elevation linefeatures.

FIG. 10 illustrates an embodiment of extending flood elevation linesusing existing flood elevation lines.

FIG. 11 illustrates an embodiment of forming a flood elevation lineusing a flood source line feature.

FIG. 12 illustrates an embodiment of forming flood elevation lines usingtwo pre-established flood elevation lines.

FIG. 13 illustrates an embodiment of approximating a flood elevationline for a point between two flood elevation lines for 100-year floodboundaries.

FIG. 14 illustrates an embodiment of approximating a flood elevationline for a point between two flood elevation lines for the 500-yearflood boundaries.

FIG. 15 illustrates another embodiment for calculating a flood elevationline for a point between two flood elevation lines.

FIG. 16 illustrates an embodiment of determining a flood elevation linefor a point outside of the 500-year flood boundary.

FIGS. 17 a-d illustrate various flood data charts used in calculating aflood frequency versus damage curve, according to an embodiment.

FIG. 18 a illustrates an embodiment of a distribution for average annualloss.

FIG. 18 b illustrates an embodiment of a chart calculating an averageannual loss.

FIG. 19 illustrates a chart of risk scores, according to an embodiment.

FIG. 20 illustrates an embodiment of a method for calculating theaverage annual loss due to flooding at a property point.

FIG. 21 illustrates an embodiment of a method for using flood elevationdata to calculate a distribution for flood frequency versus floodelevation.

FIG. 22 illustrates an embodiment of a method for forming a floodelevation line by aligning elevations on a flood boundary.

FIG. 23 illustrates an embodiment of a method for forming a floodelevation line based on a pre-existing flood elevation lines.

FIG. 24 a-b illustrate an embodiment of a method for forming a rastersurface based on flood elevations.

FIG. 25 illustrates an embodiment of a method for forming a floodelevation line based on gage station data.

FIG. 26 illustrates an embodiment of a method for forming a floodelevation line by extending a pre-existing elevation line.

FIG. 27 illustrates an embodiment of a method for forming a base floodelevation line by using a centerline.

FIG. 28 illustrates an embodiment of a method for using two perimeterflood elevation lines for forming subsequent intermediary floodelevation lines.

FIG. 29 illustrates an embodiment of a method for forming a floodelevation line for a point between two pre-existing flood elevationlines.

FIG. 30 illustrates an embodiment of a method for forming a floodelevation line for a point using two pre-existing flood elevation lines.

FIG. 31 illustrates an embodiment of a method for providing a flood riskassessment for a point.

FIG. 32 illustrates an embodiment of a web-based method for providing aflood risk assessment for a point.

FIGS. 33 a-b illustrate an embodiment of a method for correcting a floodelevation line.

FIG. 34 illustrates an embodiment of a method for redefining at least aportion of a flood boundary.

FIGS. 35 a-b illustrate an embodiment of a method for correcting a floodboundary using a digital elevation map.

FIGS. 36 a-b illustrate an embodiment of a method for determining floodfrequency versus flood elevation points using three dimensionalsurfaces.

FIG. 37 illustrates an embodiment of a flood water surface profile.

FIG. 38 a illustrates an embodiment of a plot of N-segment discretehydrological data series.

FIG. 38 b illustrates an embodiment of sorted gage station data for usein determining the N-segment discrete hydrological data series.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. Itshould be understood, however, that the drawings and detaileddescription thereto are not intended to limit the invention to theparticular form disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the present invention as defined by the appendedclaims. Note, the headings are for organizational purposes only and arenot meant to be used to limit or interpret the description or claims.Furthermore, note that the word “may” is used throughout thisapplication in a permissive sense (i.e., having the potential to, beingable to), not a mandatory sense (i.e., must). The term “include”, andderivations thereof, mean “including, but not limited to”. The term“coupled” means “directly or indirectly connected”.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In various embodiments, a flood frequency versus flood elevation (flooddepth) curve may be computed for a property point (e.g., a geocodedpoint location defined using geospatial coordinates, such as a latitudeand a longitude, a georeferenced point (e.g., referenced to a coordinatesystem), an address, a building at an address, or other points ofinterest (POI)) in a flood risk area. In some embodiments, the floodfrequency versus flood elevation curves may be determined for severalproperty points in a portfolio. While FEMA is suggested as a possiblesource of flood maps herein, it is to be understood that the methodsdescribed herein may be used for property points worldwide (e.g., notconstrained to the United States). For example, other flood map sourcesmay be used to assist in analyzing property points located outside theUnited States. The flood frequency may refer to a flood level that has aspecified percent chance of being equaled or exceeded in a given year.For example, a 100-year flood may occur on average once every 100 yearsand thus may have a 1-percent chance of occurring in a given year. Insome embodiments, the flood frequency may be in decimal format (e.g.,0.01 for the 100 year flood (0.01= 1/100 years) or a maximum flood eventoccurring statistically once every 100 years, 0.002 for the 500 yearflood (0.002= 1/500 years) or a maximum flood event occurringstatistically once every 500 years). In some embodiments, exceedanceprobability may be used instead of or in addition to flood frequency.Exceedance probability may refer to a probability of a value exceeding aspecified magnitude in a given time period. For example, the data on aflood frequency curve may also be plotted as an exceedance probabilitycurve. Other flood frequencies and flood frequency formats are alsocontemplated. Flood elevation may indicate an elevation of the surfaceof flood waters during the corresponding flood event. For example, ifthe flood water surface rises to an elevation of 180 m (e.g., above sealevel) at a property point during a flood event occurring statisticallyonce every 100 years, the 100 year flood elevation for the propertypoint may be 180 m. Other flood elevation formats are also contemplated(e.g., the flood elevation may be represented as a flood depth of theflood waters above the ground surface (e.g., 10 feet above the groundsurface), etc.).

Initial flood datasets may be provided by several sources. For example,datasets may be provided from flood maps such as digital flood zoningmaps (for example, Digital Flood Insurance Rate Maps (DFIRM) (e.g., fromthe Federal Emergency Management Agency (FEMA)). Flood maps may includeflood risk zoning maps adopted by communities that participate in theNational Flood Insurance Program. Other flood maps are alsocontemplated. Flood maps may be stored in geospatial databases. Othersources of initial flood map datasets are also contemplated (e.g.,datasets may originate from flood elevation lines or from floodelevation raster images). Additional data may be derived from 1-10 mDigital Elevation datasets (“1-10 m” may indicate a resolution of themaps), USGS (United States Geological Survey) gage station records, andflood source features from USGS National Hydrologic Datasets. Otherresolution (e.g., higher resolution) digital elevation datasets are alsocontemplated. These initial datasets may only provide a single point ata flood frequency versus flood elevation curve for a given geographiclocation (e.g., a given property point) in a flood risk area (e.g., the100-year base flood elevation). For example, these datasets may providethe flood elevation line for a 100-year (and/or 500-year) flood(100-year and 500-year refer to flood frequency) for a set of points. Insome embodiments, the flood frequency versus flood elevation curve maybe computed for geospatial points (e.g., property points) based on, forexample, two statistically determined discrete points (such as 100-yearand 500-year flood elevations) derived from a flood map (e.g., a digitalflood risk boundary map), flood elevation lines for flood elevations,and digital elevation data. In some embodiments, the two points may notbe statistically determined discrete points. Based on these determinedpoints, flood frequency versus damage curves may be calculated to assistin flood risk assessment (e.g., to assist in insurance premiumdeterminations for a property point). In some embodiments, prior tocalculating the two points, missing data (e.g., missing flood elevationlines and/or flood boundaries) may be computed (e.g., using the methodsdescribed herein). In some embodiments, existing or derived floodelevation lines and/or flood boundaries may also be corrected (e.g.,using the methods described herein).

FIG. 1 illustrates an embodiment of a WAN 102 and a LAN 104. WAN 102 maybe a network that spans a relatively large geographical area. TheInternet is an example of a WAN 102. WAN 102 typically includes aplurality of computer systems that may be interconnected through one ormore networks. Although one particular configuration is shown in FIG. 1,WAN 102 may include a variety of heterogeneous computer systems andnetworks that may be interconnected in a variety of ways and that mayrun a variety of software applications.

One or more LANs 104 may be coupled to WAN 102, LAN 104 may be a networkthat spans a relatively small area. Typically, LAN 104 may be confinedto a single building or group of buildings. Each node (i.e., individualcomputer system or device) on LAN 104 may have its own CPU with which itmay execute programs. Each node may also be able to access data anddevices anywhere on LAN 104. LAN 104, thus, may allow many users toshare devices (e.g., printers) and data stored on file servers. LAN 104may be characterized by a variety of types of topology (i.e., thegeometric arrangement of devices on the network), of protocols (i.e.,the rules and encoding specifications for sending data, and whether thenetwork uses a peer-to-peer or client/server architecture), and of media(e.g., twisted-pair wire, coaxial cables, fiber optic cables, and/orradio waves).

Each LAN 104 may include a plurality of interconnected computer systemsand optionally one or more other devices. For example, LAN 104 mayinclude one or more workstations 110 a, one or more personal computers112 a, one or more laptop or notebook computer systems 114, one or moreserver computer systems 116, and one or more network printers 118. Asillustrated in FIG. 1, an example LAN 104 may include one of eachcomputer systems 110 a, 112 a, 114, and 116, and one printer 118. LAN104 may be coupled to other computer systems and/or other devices and/orother LANs through WAN 102.

One or more mainframe computer systems 120 may be coupled to WAN 102. Asshown, mainframe 120 may be coupled to a storage device or file server124 and mainframe terminals 122 a, 122 b, and 122 c. Mainframe terminals122 a, 122 b, and 122 c may access data stored in the storage device orfile server 124 coupled to or included in mainframe computer system 120.

WAN 102 may also include computer systems connected to WAN 102individually and not through LAN 104. For example, workstation 110 b andpersonal computer 112 b may be connected to WAN 102. For example, WAN102 may include computer systems that may be geographically remote andconnected to each other through the Internet.

FIG. 2 illustrates an embodiment of computer system 250 that may besuitable for implementing various embodiments of a system and method forflood risk assessment. Each computer system 250 typically includescomponents such as CPU 252 with an associated memory medium such asCD-ROMs 260. The memory medium may store program instructions forcomputer programs. The program instructions may be executable by CPU252. Computer system 250 may further include a display device such asmonitor 254, an alphanumeric input device such as keyboard 256, and adirectional input device such as mouse 258. Computer system 250 may beoperable to execute the computer programs to implementcomputer-implemented systems and methods for flood risk assessment.

Computer system 250 may include a memory medium on which computerprograms according to various embodiments may be stored. The term“memory medium” is intended to include an installation medium, e.g.,floppy disks or CD-ROMs 260, a computer system memory such as DRAM,SRAM, EDO RAM, Rambus RAM, etc., or a non-volatile memory such as amagnetic media, e.g., a hard drive or optical storage. The memory mediummay also include other types of memory or combinations thereof. Inaddition, the memory medium may be located in a first computer, whichexecutes the programs or may be located in a second different computer,which connects to the first computer over a network. In the latterinstance, the second computer may provide the program instructions tothe first computer for execution. Computer system 250 may take variousforms such as a personal computer system, mainframe computer system,workstation, network appliance, Internet appliance, personal digitalassistant (“PDA”), television system or other device. In general, theterm “computer system” may refer to any device having a processor thatexecutes instructions from a memory medium.

The memory medium may store a software program or programs operable toimplement a method for flood risk assessment. The software program(s)may be implemented in various ways, including, but not limited to,procedure-based techniques, component-based techniques, and/orobject-oriented techniques, among others. For example, the softwareprograms may be implemented using ActiveX controls, C++ objects,JavaBeans, Microsoft Foundation Classes (“MFC”), browser-basedapplications (e.g., Java applets), traditional programs, or othertechnologies or methodologies, as desired. A CPU such as host CPU 252executing code and data from the memory medium may include a means forcreating and executing the software program or programs according to theembodiments described herein.

Various embodiments may also include receiving or storing instructionsand/or data implemented in accordance with the foregoing descriptionupon a carrier medium. Suitable carrier media may include storage mediaor memory media such as magnetic or optical media, e.g., disk or CD-ROM,as well as signals such as electrical, electromagnetic, or digitalsignals, may be conveyed via a communication medium such as a networkand/or a wireless link.

FIGS. 3, 4 a, and 4 b illustrate an embodiment of an example flood mapand plotted curves of a flood elevation versus flood frequency points onthe example flood map. As seen in FIG. 3, flood elevation lines 305(e.g., base flood elevation (BFE) line 305 a) may be provided for aposition (e.g., position 309 a corresponding to a property point) on the100-year flood boundary 301 from a flood source line feature (forexample, a waterway centerline 307 (e.g., a river centerline)). Forexample, plot point 311 a (see FIGS. 4 a-b) may represent the floodelevation for position 309 a for the 0.01 flood frequency (100-yearflood frequency). To build a curve for flood frequency versus floodelevation for a position (e.g., position 309 a), a second point 311 b(e.g., for the 0.002 flood frequency (at the 500-year flood boundary303)) on the curve 313 may be needed (several embodiments fordetermining the first point 311 a and/or second point 311 b aredescribed herein). For example, if second point 311 b is known orcalculated, the curve 313 for flood frequency versus flood elevation maybe calculated, using a curve fitting algorithm, for position 309 a thatmay show other flood frequency versus flood elevations for position 309a (several embodiments for calculating the curve 313 are also describedherein). FIG. 4 b also shows other points on the flood frequency versusflood elevation curve 313 (with modified axis to show additional floodfrequencies versus flood elevations).

As defined by the National Flood Insurance Program (NFIP), base floodelevationIBFE) is “the elevation shown on the Flood Insurance Rate Mapfor Zones AE, AH, A1-A30 . . . V1-V30 and VE that indicates the watersurface elevation resulting from a flood that has a one percent chanceof equaling or exceeding that level in any given year.” The BFE is theelevation of the water projected to occur in association with the baseflood, which by definition is a “flood having a one percent chance ofbeing equaled or exceeded in any given year” see 44 C.F.R. 59.1. As usedherein “flood elevations” and “flood elevation lines” are used to referto the elevation of floods and lines representing these elevations forvarious flood frequencies (e.g., 500-year flood). “Flood elevation line”for the 100-year flood frequency may be used interchangeably with theterm “BFE”.

FIG. 5 illustrate an embodiment of a method for providing a floodelevation and flood risk assessment for a property point. It should benoted that in various embodiments of the methods described below, one ormore of the elements described may be performed concurrently, in adifferent order than shown, or may be omitted entirely. Other additionalelements may also be performed as desired.

At 501, a property point may be provided by a user (e.g., the address ofa targeted portfolio from a mortgage company, public sector entity(e.g., FEMA, municipalities, states, etc.), capital market entity,insurance company, or reinsurance company).

At 503, the property point may be geocoded (e.g., an x,y coordinate(such as a latitude/longitude) may be determined by the system).

At 505, a substantially perpendicular line may be formed on a digitalelevation map, between the property point and a flood source linefeature of a flood source in a same catchment area as the property. Thesubstantially perpendicular line may be used to associate the propertypoint with the flood source line feature and one or more floodboundaries. The perpendicular line may also be formed as a cross sectionthrough the property point (e.g., in three dimensional space). Otheruses of the perpendicular line/cross section are also contemplated.

At 507, at least two points of flood frequency versus flood elevationfor the property point may be calculated using a flood map and a digitalelevation map. As described herein, calculating the at least two pointsmay include statistically determining the at least two flood frequencyversus flood elevation points. For example, the 100-year flood elevationand the 500-year flood elevations may be determined for the propertypoint (e.g., according to flood elevation lines, corresponding to floodfrequency boundaries, crossing through the property point). In someembodiments, other flood elevations may be determined for the propertypoint in addition to or instead of the 100-year base flood elevation andthe 500-year flood elevation. Flood maps may include maps of flood zones(defined by flood boundaries) and a plurality of pre-existing floodelevation lines. For example, FEMA Flood Insurance Rate Maps may have100-year flood elevation lines printed on them for some areas. In someembodiments, FEMA maps may have the 500-year flood boundary printed onthem for some areas, but may not have 500-year flood elevation linesprinted on them. In some embodiments, the 100-year and/or 500-year floodelevation lines may be determined or provided from other flood mapsources (e.g., a FEMA Flood Insurance Study (FIS)). Digital elevationmaps may include digital elevation models and/or digital elevationdatasets. Other maps and datasets may also be used for elevation.

In some embodiments, the 100-year and 500-year flood elevations/floodelevation lines for a region (e.g., a state or the nation) may bedetermined using, for example, the process designated in FIG. 6 prior toreceiving the property point request. These predetermined floodelevations may be stored in 100-year and 500-year flood elevationlayers. These layers may then be queried after the property pointrequest is received. In some embodiments, the 100-year and 500-yearflood elevations may be determined during runtime (e.g., after theproperty point request is received) using the process designated, forexample, in FIG. 6. Determining the 100-year and 500-year floodelevation lines may be automated or may be manual. Again, while severalexamples are provided using the 100-year and 500-year flood elevations,it is to be understood that other flood elevations may be used instead.Other methods are also contemplated and described herein. For example,at least two points of flood frequency versus flood elevation for theproperty point may be determined at the intersection of a cross section,through the property point, and flood frequency surfaces (e.g., the 100year flood surface and the 500 year flood surface) (e.g., see FIGS. 36a-b). As another example, corresponding flood elevations for floodfrequencies may be determined at an intersection of a line (through theproperty point and substantially perpendicular to a flood source linefeature) and the corresponding flood boundaries (e.g., see FIGS. 13-14).As yet another example, the at least two points of flood frequencyversus flood elevation for the property point may be calculated usingcross section data on a flood profile (e.g., see FIG. 37). Other methodare also contemplated.

At 509, a relationship between flood frequency and flood elevation forthe property point may be defined using the at least two points. Forexample, a flood frequency versus flood elevation curve may bedetermined at the property point. Using the 100-year and 500-year floodelevation points, a distribution may be calculated. The distribution mayprovide the flood elevation at other flood frequencies (e.g., 10 year,50 year, 1000 year, etc.). For example, the distribution may be alogarithmic relationship (e.g., see FIG. 4 c). One logarithmicrelationship that may be used is:

Flood Elevation=a Log(flood return period)+b

where flood return period=1/flood frequency and where a and b aredefined by solving the equation for the at least two calculated pointsof flood frequency versus flood elevation. To develop this linearrelationship (e.g., see FIG. 4 c), several data sets for different areaswere analyzed. Other logarithmic relationships are also contemplated(e.g. see below).

At 511, at least one flood elevation at a flood frequency different fromthe flood frequency of one of the at least two points for the propertypoint may be predicted using the defined relationship. For example, ifthe relationship is represented as a curve, a flood elevation at acorresponding flood frequency may be determined from the curve. If therelationship is defined as an equation, a flood elevation for acorresponding flood frequency may be determined using the definedequation. Other relationships are also contemplated.

At 513, a flood frequency versus flood damage distribution may becalculated for the property point using the flood frequency versus floodelevation curve and a flood damage versus flood elevation relationship(e.g., a vulnerability curve provided by the user). Additional data mayalso be used (e.g., provided by the user about the property point).

At 515, an average annual loss for the property point may be calculatedusing the distribution of flood frequency versus flood damage (e.g., byinterpolation). In some embodiments, information may be used to providea flood risk assessment report to the user. In some embodiments, a floodelevation versus percent damage relationship may be defined (e.g., usingone or more flood studies for the property area) and the average annualloss for the property point may be determined using the flood elevationversus percent damage relationship.

As seen in FIG. 6, at 551, a determination may be made as to whether theproperty point is within a 100-year flood zone, a 500-year flood zone,or neither. Other flood frequency flood zones may also be used. If theproperty point is within the 100-year flood zone and/or the 500-yearflood zone, the 100-year and 500-year flood elevations for the propertypoint may be determined. Other flood elevations are also contemplated.At 553, a determination may be made whether the 100-year base floodelevation lines exist near the property point. At 555, if the 100-yearbase flood elevation lines exist near the property point, the 100-yearbase flood elevation for the point may be interpolated from the existing100-year base flood elevation lines (e.g., sec FIG. 13). At 557, if the100-year base flood elevation lines are not provided near the point, the100-year base flood elevation lines may be created near the point (e.g.,see FIGS. 7 a-8 b, and 11-12) and the 100-year base flood elevation forthe point may be interpolated. At 559, a determination may be madewhether the 500-year flood elevation lines exist near the propertypoint. At 561, if the 500-year flood elevation lines exist near theproperty point, the 500-year flood elevation for the point may beinterpolated from the existing 500-year flood elevation lines (e.g., seeFIG. 14). At 563, if the 500-year flood elevation lines are not providednear the point, the 500-year flood elevation lines may be created nearthe point (e.g., see FIGS. 10-12) and the 500-year flood elevation forthe point may be interpolated. At 565, if the property point is outsidethe 100-year and 500-year flood elevation lines, the 100-year and500-year flood elevations may be determined for the point using variousmethods such as extrapolation/interpolation (e.g., see FIG. 16) and/orusing the nearest 100-year/500-year flood elevation lines. In someembodiments, the 100-year and 500-year flood elevation lines may bedetermined for an area (e.g., a nationwide area) at one time. The100-year and 500-year flood elevations may then be interpolated for theproperty points as needed. In some embodiments, existing or derivedflood elevation lines and/or flood boundaries may also be corrected(e.g., see FIGS. 33-36).

Referring back to FIG. 3, in some embodiments, different probabilitydistributions may be used to calculate the curve 313 with two or morepoints 311 a and 311 b (which may be statistically determined floodelevation points). For example, the Log Pearson Type III distribution,the Log Normal distribution, and/or the Extreme Value Type Idistribution may be used. Other distributions may also be used. Themagnitude of a flood event (flood elevation) and the corresponding floodfrequency may have a non-linear relationship. The flood elevation in therelationship may change more significantly during smaller floodfrequencies (e.g., 5, 10-year return periods) than longer floodfrequencies (e.g., 500 year return periods). In some embodiments, therelationship between flood elevations and flood frequency in a range offlood frequency between approximately 50 years to 1000 years may benear-linear after applying a logarithm transform on the flood frequencybase. In some embodiments, a logarithm relationship between floodelevation and flood frequency may be defined at a cross section throughthe property point (and perpendicular to the flood source line feature)as:

Flood Elevation=a Log(flood return period)+b

In this relationship “a” may be the slope and “b” may be a constant thatmay be determined by solving the relationship with two floodelevation/flood frequency point pairs. In some embodiments, for a 100year flood frequency point and a 500 year flood frequency, therelationship may be:

Flood Elevation=1.431*(Elev500−Elev100)*Log(flood returnperiod)+3.862*(Elev100)−2.862*Elev500

where Elev100 is the flood elevation at flood frequency of 0.01 (the 100year flood) and Elev500 is the flood elevation at the 0.002 floodfrequency (500 year flood). The relationship may provide a floodelevation for a given flood frequency at the property point. Therelationship may account for hydrologic, hydraulic, and statisticalcharacteristics of flood elevation versus flood frequency. In someembodiments, the cross section through the property point (andperpendicular to the flood source line feature) may associate theproperty point with the flood source based on characteristics ofwatershed, elevation, and/or flow direction.

In some embodiments, the curve 313 may be calculated using the LogPearson Type III distribution. The Log Pearson Type III distribution mayinclude two parameters (a scale parameter and a shape parameter) and aninitial hydrologic condition factor (such as initial discharge or areference elevation). The Log Pearson Type III distribution may becalculated as follows:

${P(y)}:={{\frac{\lambda^{\beta}*(y)^{\beta - 1}*{\exp \lbrack {{- \lambda}*(y)} \rbrack}}{\Gamma (\beta)}{\Gamma ( {\beta + 1} )}} = {\beta!}}$

where λ is a scale parameter and β is a shape parameter. The scale andshape parameters may be determined using the two points 311 a and 311 b(for example, the two points may provide two sets of values for (P(y),y)resulting in two equations (with specified initial conditions) of twounknowns (the scale parameter and shape parameter)). In someembodiments, P(y) may represent, for example, the flood frequency and ymay represent the flood elevation (e.g., P(y)=0.01, y=120 ft). Thedetermined scale parameter and shape parameter may then be used tocalculate the curve 313 (for a specified initial condition).

In some embodiments, the Lognormal Distribution may be used to calculatethe curve 313. A variable X may be log-normally distributed if Y=LN(X)is normally distributed with “LN” denoting the natural logarithm. Thegeneral formula for the probability density function of the lognormaldistribution may be:

${{{f(x)} = {{\frac{^{- {({{({\ln {({{({x - \theta})}/m})}})}^{2}/{({2\sigma^{2}})}})}}}{( {x - \theta} )\sigma \sqrt{2\pi}}\mspace{14mu} x} \geq \theta}};m},{\sigma > 0}$

where σ is the scale parameter, θ is the location parameter and m is theshape parameter. In some embodiments, points 311 a and 311 b may be usedto solve for at least two of θ, σ, and m. The case where θ equals zeromay be referred to as the 2-parameter log-normal distribution. In someembodiments, additional points of flood frequency versus flood elevationmay be used. The points 311 a and 311 b may be used to solve for σ and mto calculate the curve 313 (e.g., by providing two sets of values for(f(x),x) resulting in two equations of two unknowns.) In someembodiments, f(x) may represent the probability and x may represent theflood elevation. The case where θ=0 and m=1 may be referred to as thestandard lognormal distribution. The equation for the standard lognormaldistribution may be:

${{f(x)} = {{\frac{^{- {({{({\ln \; x})}^{2}/{({2\sigma^{2}})}})}}}{x\; \sigma \sqrt{2\pi}}\mspace{14mu} x} \geq 0}};{\sigma > 0}$

In some embodiments, either point 311 a and 311 b may be used to solvefor a in the standard lognormal distribution to calculate the curve 313.The general form of probability functions may be expressed in terms ofthe standard distribution.

In some embodiments, the Extreme Value Type I distribution may be used:

${{f(x)} = {{{\frac{1}{\beta}^{\frac{x - \mu}{\beta}}^{- ^{\frac{x - \mu}{\beta}}}} - \infty} < x < \infty}},{\beta > 0}$${{F(x)} = {{1 - ^{- ^{\frac{x - \mu}{\beta}}} - \infty} < x < \infty}},{\beta > 0}$

In some embodiments, points 311 a and 311 b may be used to solve for βand μ to calculate the curve 313 (e.g., by providing two sets of valuesfor (f(x),x) resulting in two equations of two unknowns.) In someembodiments, f(x) may represent the probability and x may represent theflood elevation.

In some embodiments, the Log Pearson Type III distribution, the LogNormal distribution, and/or the Extreme Value Type I (or anotherdistribution) may be used to calculate the curve 313. Once theparameters are solved for the distribution (e.g., using the points 311 aand/or 311 b), flood elevations at different flood frequency levels(e.g., 2 year, 5 year, 10 year, 50 year, 100-year, 200 year, 500-year,and 1000 year) may be determined using the distribution.

For example, in some embodiments, discrete values of the flood frequencyversus flood elevation relationship at two known points (e.g., (FF1,Elev1), (FF2, Elev2)) may be entered into the selected probabilitydistribution with two unknown parameters (e.g., shape parameter andscale parameter) to form two equations with two unknown variables:

FF1=F(Elev1,Shape Parameter,Scale Parameter)

FF2=F(Elev2,Shape Parameter,Scale Parameter)

The equations may be solved mathematically for deriving the values ofthose parameters (e.g., the shape parameter and scale parameter). Afterthose two parameters are determined, the flood frequency versuselevation relationship may be presented as the following:

FF=F(Elev,Shape Parameter,Scale Parameter)

With this equation, the flood elevation at different flood frequencies(e.g., 2 yr, 10 yr, 50 yr, 200 yr, 1000 yr . . . ) may be computed.

In some embodiments, other relationships may be used. For example, asseen in FIG. 38 a, hydrological parameters may be calculated usingN-segment discrete hydrological data series derived from hydrologic gagestation data. Gage station data may include date, gage height, andstream flow data. The average discharge and coefficient of variation (anormalized standard deviation) for an n-segment hydrologic dataset maybe calculated using the following formulas:

$\mspace{79mu} {{\overset{\_}{Q}}_{n} = {\frac{1}{N_{n}}\lbrack {\text{?} + {( {N_{n} - m_{n}} ){\overset{\_}{Q}}_{n - 1}}} \rbrack}}$$\mspace{79mu} {\text{?} = \{ {\frac{1}{N_{n} - 1}\lbrack {{\text{?}( {\frac{Q_{z}}{{\overset{\_}{Q}}_{n}} - 1} )^{2}} + {( {N_{n} - m_{n} - 1} )\text{?}}} \rbrack} \}^{\frac{1}{2}}}$$\mspace{79mu} {S_{n} = {{\overset{\_}{Q}}_{n}\text{?}}}$?indicates text missing or illegible when filed

N_(i)=number of years in the ith time period from right to left, i=0, 1,2, . . . n; and,m_(i)=number of floods in the ith discrete segment from right to theleft i=0, 1, 2, . . . nWhere Q _(n)=mean discharge of the hydrologic dataset; C_(V) _(n)=coefficient of river discharge; and S_(n)=standard deviation. Curvefitting on the standard probability distributions may be used todetermine three key hydrologic parameters by using hydrologic datasets:mean discharge ( Q _(n)) standard deviation (S_(n)), and skewcoefficient. The skew coefficient may be derived from the mean dischargeand its standard deviation. The Log-Pearson Type III deviate may beobtained by using the skew coefficient. Using the mean discharge,coefficient of river discharge and standard deviation, the scaleparameter λ and shape parameter β of the Log Pearson Type IIIdistribution may be determined (e.g., from statistical look-up tables).The derived probability distribution may present a relationship betweenthe flood frequency and discharge. By using the relationship between thedischarge and flood elevation (rating curve) from the gage station data(sec FIG. 38 b), the flood frequency versus flood elevation relationshipmay be derived.

In some embodiments, gage station data over a series of years may besorted by discharge and/or gage height in order of largest flood eventfirst, second event second, etc. (e.g., see FIG. 38 b with a partiallisting). The number of years covered by the gage station may be used todetermine probability of a flood event happening in a given floodfrequency. For example, the conditional probability (corresponding toflood frequency) may be provided by the following formulas:

${P_{n} = \frac{m}{N_{n} - 1}},{m = 1},2,\ldots \mspace{14mu},m_{n}$${P_{n - 1} =  P_{n} \middle| {m_{n} + {\frac{{Nn} - {mn}}{N_{n}}*\frac{m}{N_{n - 1} + 1}}} },{m = 1},2,\ldots \mspace{14mu},m_{n - 1}$${P_{1} =  P_{2} \middle| {m_{2} + {\frac{{N\; 2} - {m\; 2}}{N_{2}}*\frac{m}{N_{1} + 1}}} },{m = 1},2,\ldots \mspace{14mu},m_{1}$${P_{0} =  P_{1} \middle| {m_{1} + {\frac{{N\; 1} - {m\; 1}}{N_{1}}*\frac{m}{N_{0} - K + 1}}} },{m = 1},2,\ldots \mspace{14mu},m_{0}$

N_(i)=number of years in the ith time period from right to left, i=0, 1,2, . . . n; and,m_(i)=number of floods in the ith discrete segment from right to theleft i=0, 1, 2, . . . nK=number of the floods which were taken to a extreme flood segment

FIG. 38 b illustrates a partial listing of flood frequencies computedusing the above formulas. The gage height may be converted into floodelevation by adding the gage datum (which may be the elevation of thegage station above sea level). In some embodiments, two or more pointsof flood frequency versus flood elevation may thus be computed usinggage station data for a property point.

In some embodiments, these hydrologic parameters may be computed to beused in detailed HH studies and modeling in areas where flood mappingand flood engineering data may be missing. HH studies may includehydrologic studies (e.g., using water cycles and water movementmodeling) and hydraulic studies (e.g., using gravity and water flowmodeling) to determine approximate locations of flood boundaries, floodsource line features, and/or flood elevation lines.

In some embodiments, data may be used (e.g., from DFIRM studies) toevaluate which of the three distributions may be best for a specificregion or regions. In some embodiments, one distribution may be used. Insome embodiments, different distributions may be used for differentregions. The algorithm to derive the parameters for the distributions byusing the two points (e.g., at the 100-year and the 500-year floodelevations) may be performed by a computer system or performed manually.The output of the distribution (e.g., the flood elevation at the 2 year,5 year, 10 year, 50 year, 100-year, 200 year, 500-year, and 1000 year,etc. flood frequencies) may be provided for additional flood analysis.

In various embodiments, the data for points 311 a and 311 b may bederived from flood elevation lines on flood maps from various datasets.For example, FIG. 7 a illustrates a digital elevation base map 600(which may have a resolution of 10 m (other resolutions are alsocontemplated)) with a river centerline 607, 100-year flood boundary 601with flood elevation lines 605 (e.g., flood elevation line 605 a) andelevation labels 609. The flood elevation lines 605 may be drawn byconnecting points of similar elevations on the flood zone boundaries.For example, flood elevation line 605 a is drawn connecting 190 ftelevations on the 100-year flood boundary 601. This may be drawnmanually by physically drawing the lines or drawing the lines manuallyusing a computer, or may be done automatically (e.g., softwareimplemented). In some embodiments, the line may not actually be drawn,but instead data associated with the lines may be stored (e.g., in adatabase). In some embodiments, the elevations at the flood zoneboundary may be labeled to assist in the flood elevation line 605formation.

As seen in FIG. 7 b, in some embodiments, several flood elevation linesand/or portions of the 100-year flood boundary 601 (or othercorresponding flood boundary) may be missing. In some embodiments, thesedata gaps in the flood risk zoning datasets may be filled (e.g., tobuild national coverage of flood elevation lines). Gaps may include datagaps between adjacent communities, large gaps between upstreamcommunities and downstream communities, and no data areas. In someembodiments, the missing flood elevation lines and/or flood boundary maybe created/redefined to assist in determination of the two points offlood frequency versus flood elevation for a property point (e.g., aproperty point in the region of missing flood elevation lines and/orflood boundary). In some embodiments, existing flood elevation lines(e.g., flood elevation lines 605 b-e) on flood map 700 may be used toguide the orientation and/or size of the missing flood elevation lines(e.g., flood elevation line 605 f). In addition, the last known upstreamelevation points 609 c,d of the 100-year flood boundary 601 and thefirst known downstream elevation points 609 e,f of the 100-year floodboundary 601 may be used to determine the approximate initial elevationpoints for the missing flood elevation lines. For example, elevationpoint 609 c may be 204 ft and elevation point 609 e may be 194 ft. Theplacement of missing flood elevation lines may be based on the generalslope of the flood profile in from upstream or downstream areas where HHstudies exist. Initial elevation points every 2 ft between these twopoints could be used (e.g., elevation points at 202 ft, 200 ft, 198 ft,196 ft) for the missing elevations needed for the missing floodelevation lines. Other elevation intervals may also be used. In someembodiments, a flood map may be overlaid (e.g., geographically alignedusing one or more similar geographic features or coordinates between thetwo maps) on an elevation map (e.g., a digital elevation map). In someembodiments, the flood map and the elevation map may be digital maps. Insome embodiments, overlaying the maps may include aligning digitalcoordinates of the maps (e.g., on graphical maps and/or respective datasets). In some embodiments, drawing, connecting, moving, adjustingpoints/lines on the digital maps may include drawing, connecting,moving, adjusting points/lines on one or both the digital elevation mapand flood map. The placements of the indicated elevations (e.g.,elevation points 202 ft, 200 ft, 198 ft, 196 ft) on both sides of thecenterline 607 may be, for example, highlighted and connected (e.g.,flood elevation line 605 f may be drawn connecting elevation points 198ft on either side of the centerline 607). The slope and size of existingflood elevation lines (e.g., flood elevation lines 605 c and 605 d) maybe used to search for corresponding elevation points on opposing sidesof the centerline 607 to connect. For example, an area approximately thelength of flood elevation line 605 c away from (and at a slope of 605 c)the initial elevation point 609 a may be searched for a similarelevation point (e.g., elevation point 609 b) for creating the missingflood elevation line 605 f. This may be helpful especially if there areseveral similar elevation points on the opposing side of the centerline607.

In some embodiments, the slope and length of a temporary line used tosearch for a matching elevation point may be determined based on aweighted average of the length and slope of flood elevation line 605 cand 605 d. For example, the closer the initial elevation point 609 a isto flood elevation line 605 c, the more a temporary line may resemblethe flood elevation line 605 c in length and slope. In some embodiments,a length of the temporary line (length_temp) may be determined asfollows (with distance to flood elevation line 605 c=dist605 c; distanceto flood elevation line 605 d=dist605 d; length of flood elevation line605 d=length605 d; and length of flood elevation line 605 c=length605c);

${length\_ temp} = {{\frac{{dist}\; 605\; c}{{{dist}\; 605\; c} + {{dist}\; 605\; d}}*{length}\; 605\; d} + {\frac{{dist}\; 605\; d}{{{dist}\; 605\; c} + {{dist}\; 605\; d}}*{length}\; 605\; c}}$

The distance between the point and the flood elevation line may equalthe shortest distance between the initial elevation point 609 a and theflood elevation line. Other distances are also contemplated. In someembodiments, the slope of the temporary line (slope_temp) may bedetermined as follows (with slope of flood elevation line 605 c=slope605c and slope of flood elevation line 605 d=slope605 d):

${slope\_ temp} = {{\frac{{dist}\; 605\; c}{{{dist}\; 605\; c} + {{dist}\; 605\; d}}*{slope}\; 605\; d} + {\frac{{dist}\; 605\; d}{{{dist}\; 605\; c} + {{dist}\; 605\; d}}*{slope}\; 605\; c}}$

Other methods of determining ratios for slopes and/or lengths are alsopossible. The temporary line may be drawn using the calculated slope andlength. The elevation points on the other side of the flood elevationline may then be searched for an elevation point approximately the sameas the initial elevation point 609 a. The flood elevation line 605 ffrom the initial elevation point 609 a to the determined elevation point609 b may then replace the temporary line. The flood elevation line 605f may be assigned an elevation approximately equal to the average of theinitial elevation point 609 a and the determined elevation point 609 b.

In some embodiments, (e.g., at the 100 year flood frequency) theplacement of new BFE lines may be based on a general slope (e.g., basedon hydraulic principles) between upstream BFEs, downstream BFEs, and theelevation data. For example:

Slope=(Upstream BFE−Downstream BFE)/Distance between the two BFE lines

In some embodiments, if the location is known upstream and downstreamand the 500 year water surface elevations are available, the placementof new 500 year water elevation line features may be based on a generalslope (e.g., based on hydraulic principles) between the known upstreamand downstream water surface elevation locations and the elevation data.For example:

Slope=(Upstream Water Surface Elevation−Downstream Water SurfaceElevation)/Distance between two known surface elevation locations

If the 500 year slope is not available, the 100 year flood profile slopemay be used (e.g., see FIG. 37). Example elevation profiles (e.g., fromFEMA studies) among different flood frequencies may be presented to showhow the water surface may be extrapolated between two known points.

As seen in FIG. 8 a, in some embodiments, if the flood zone boundaryand/or the flood elevation lines are not available for an area, UnitedStates Geological Survey (USGS) gage station data may be used to chartand analyze stream discharge records, build the flood frequency versusdischarge curve, build the discharge versus stage curve, and derive theflood frequency versus stage relationship. For example, data from gagestation 801 is charted in FIG. 8 b. Flood event 1 may have been anactual flood recorded at gage station 801. Flood event 1 may havecorresponded to a flood elevation of 124.5 ft. By looking at the flooddata for the gage station over time, an annual probability of occurrence(i.e., probability that a similar flood of similar elevation will occurin a given year) and a corresponding flood frequency (i.e., probabilitya flood elevation will exceed the flood elevation in a given year) maybe developed for the flood events. This data may be used with elevationdata (e.g., in flood map 800) in a statistical and hydrologic analysisto predict the flood elevations (e.g., 100-year and/or 500-year floodelevations) for various flood boundaries (e.g., the 100-year floodboundary 601 and/or the 500-year flood boundary.) This data may also beused to provide flood boundaries (e.g., the 100-year flood boundaryand/or 500-year flood boundary). In some embodiments, discharge ratescould be determined to assist in the hydrologic and hydraulic analysis.In addition, other data (e.g., downstream flood zone boundaries) mayalso be used in the analysis to predict the missing flood elevationlines (e.g., flood elevation line 605 g). In some embodiments, othermodel data (e.g., FEMA HAZUS-MH (Hazards US Multi-Hazards, WatershedInformation System (WISE), Hydrologic Engineering Center River AnalysisSystem (HEC-RAS)) flood model data with DEM (Digital Elevation Model))(e.g., with a resolution of 10 m) may also be used. Other resolutionsmay also be used. In some embodiments, a high resolution DEM may be used(e.g., a high resolution digital elevation map).

FIG. 9 illustrates an embodiment of using raster images to calculateraster layers for 100-year and 500-year flood elevations. For example,GIS software may use surface analysis and modeling capabilities tocreate extrapolated surfaces based on attribute values at points andflood elevation lines. In some embodiments, these raster layers may beused to determine flood elevations for points on the flood frequencyversus flood elevation curve.

In some embodiments, to create raster layers for 100-year floodelevations, the flood elevation lines and associated flood elevationvalues may be used as input for a surface model (such as a TIN surface)to create a raster surface 901 for 100-year flood elevations. In someembodiments, for the areas without the 100-year flood elevation lines,but with 100-year flood boundaries, the 100-year flood boundaries may beoverlaid on top of the digital elevation data (e.g., overlaid on thedigital elevation map), and points on the 100-year flood boundary lines(e.g., the point elevations) from the digital elevation data may be usedas inputs for the surface model to create the raster surface 901 for the100-year flood elevations. For example, points on the 100-year floodboundary lines may be connected to form the raster surface 901. Otherraster surfaces are also contemplated.

In some embodiments, if both 100-year flood elevation lines and floodboundaries are missing for an area, USGS gage data may be used alongwith an HH study or USGS national flood frequency curves (NFF) to obtain100-year flood elevations at a location or area. This data may becombined with known 100-year flood elevations (e.g., downstream orupstream) and used as input for the surface model to create the rastersurface 901 for 100-year flood elevations.

In some embodiments, for areas with 500-year flood boundaries, the500-year flood boundaries may be overlaid on top of the digitalelevation data and the elevations of the points along the 500-year floodboundary lines may be used as input for a surface model to create theraster surface 901 for 500-year flood elevations.

In some embodiments, for areas without the 500-year flood boundaries,USGS gage data may be used with hydrologic analysis or USGS nationalflood frequency curves (NFF) to obtain 500-year flood elevation at areasto combine with known 500-year flood elevations (e.g., downstream orupstream) as input for a surface model to create the raster surface 901for 500-year flood elevations.

In some embodiments, these raster surfaces may be queried to determinesets of flood elevations versus flood frequencies for a property point(e.g., an address). These sets may be used in the distribution todetermine the curve for the flood frequency versus flood elevation forthe property point.

In various embodiments, once the flood elevations lines are availablenear an property point, these flood elevations may be used tointerpolate/extrapolate at least two flood frequency/flood elevationpoints for the distribution. Several methods ofinterpolating/extrapolating these points are described herein.

FIG. 10 illustrates an embodiment of a map 1000 for extending new floodelevation lines using existing flood elevation lines (e.g., BFEs). Insome embodiments, flood elevation lines 1005 (e.g., flood elevation line1005 a (a BFE) on 100-year flood boundary 1001 around centerline 1007)may be extended (e.g., along their slope) to the 500-year flood boundary1003 (e.g., extended flood elevation line 1006 a indicated with a dashedline). In some embodiments, the intersection 1033 a of the extendedflood elevation line may be buffered (e.g., buffer 1021 a 10 ft oneither side of the intersection point 1033 a for a DEM map (e.g., with aresolution of 10 m)) upstream and downstream at the 500-year floodboundary 1003. The elevation points between the buffered points 1023 aand 1023 b may be compared with the elevation points between thebuffered points 1023 c and 1023 d (resulting from a buffer aroundintersection point 1033 b). In some embodiments, an elevation point ateach end (e.g., with the smallest difference) may be selected as theendpoints of the extended flood elevation line 1006 a at the 500-yearflood boundary 1003. The average of the selected elevation points may beassigned to the new flood elevation line 1006. In some embodiments, thebuffer amount may be based on the resolution of the digital elevationmap. In some embodiments, buffers may not be used and the new floodelevation line 1006 may be assigned an average approximately equal tothe two intersection points 1033 a,b.

FIG. 11 illustrates an embodiment of forming a flood elevation lineusing a flood source line feature (e.g., a centerline). In someembodiments, flood elevation line 1105 a may be drawn substantiallyperpendicular to the centerline 1007 (i.e., at a right angle 1131 to thecenterline 1007 at a point on the centerline 1007). In some embodiments,the intersections 1133 a,b of the drawn flood elevation line 1105 a maybe buffered in a similar manner as described above with respect to FIG.10 to derive adjusted endpoints for the flood elevation line 1105 a(e.g., by applying buffer 1121 a to the intersections 1133 a,b to getbuffered points 1123 a-d, selecting approximately equivalent elevationpoints on either end, and connecting the selected elevation points toreform the flood elevation line 1105 a). In some embodiments, the endsof flood elevation line 1105 a may not be buffered (e.g., the elevationsat the intersections 1133 a,b may be used as the endpoints of the floodelevation line 1105 a without adjustment (the flood elevation line 1105a may be assigned a value approximately equal to the average of the twointersected points 1133 a,b)). In some embodiments, the flood elevationline may be intersected with flood boundaries (e.g., the 100 year and/or500 year flood boundaries). The elevation (e.g., from a DEM reading) ofthe intersection points (e.g., on the property point side of thecenterline 1007) may be used to move the endpoints on the opposite sideof the centerline to points of similar elevation (e.g., points collinearwith the flood elevation line). The flood elevation line may then beprovided with endpoints of matching elevation. In some embodiments,moving an endpoint may include moving a digital point on a digital map(e.g., a digital flood map or digital elevation map).

FIG. 12 illustrates an embodiment of a map for forming flood elevationlines using pre-established flood elevation lines. In some embodiments,a user may choose points 1223 a and 1223 b on either side of centerline1007 to form flood elevation line 1206 a. The user may carefully choosethese points (e.g., guided by elevations and/or other map details) todefine an accurate flood elevation line 1206 a. In some embodiments, acomputer may determine these points. In some embodiments, a floodelevation line 1206 b may be similarly defined (e.g., by selectingpoints 1223 e,f). Using the two defined flood elevation lines 1206 a,b,additional flood elevation lines may be formed between them using theslope and/or lengths of the flood elevation lines 1206 a,b and theelevation values corresponding to the 500-year flood boundary 1003 (orother flood boundary such as the 100-year flood boundary 1001). Points(e.g., points 1223 c,d) may be selected at intervals along one side ofthe flood boundary (e.g., along the left side of the 500-year floodboundary 1003). Slopes and/or lengths of the missing flood elevationlines between the pre-established flood elevation lines 1206 a,b may beestimated using the slopes and/or lengths of the pre-established floodelevation lines 1206 a,b (e.g., by weighting an average of the slopesand/or lengths of the pre-established flood elevation lines 1206 a,baccording to, for example, a distance of the flood elevation line to bedrawn from the pre-established flood elevation lines 1206 a,b.) Forexample, flood elevation lines closer to flood elevation line 1206 a mayhave a slope similar to slope 1233 a and flood elevation lines closer toflood elevation line 1206 b may have a slope similar to slope 1233 b.Using the estimated slope (e.g., slope 1233 c), a corresponding locationon the opposing flood boundary may be determined. A point 1223 g ofsimilar elevation as the initial point (e.g., initial point 1223 c) maybe determined (e.g., using the buffer technique described above withrespect to FIG. 10). In some embodiments, the closest similar elevationpoint may be used. A flood elevation line (e.g., flood elevation line1206 c) may be drawn between the determined points and an averageelevation (e.g., average of the two opposing points) may be assigned tothe flood elevation line 1206 c.

In some embodiments, the slope and length of a temporary line used tosearch for a matching elevation point may be determined based on aweighted average of the length and slope of flood elevation line 1206a,b. For example, the closer the initial elevation point 1223 c is toflood elevation line 1206 a, the more a temporary line may resemble theflood elevation line 1206 a in length and slope.

In some embodiments, a length of the temporary line (length_temp) may bedetermined as follows (with distance to flood elevation line 1206a=dist1206 a; distance to flood elevation line 1206 b=dist1206 b; lengthof flood elevation line 1206 a=length1206 a; and length of floodelevation line 1206 b=length1206 b):

${length\_ temp} = {{\frac{{dist}\; 1206\; a}{{{dist}\; 1206\; a} + {{dist}\; 1206\; b}}*{length}\; 1206\; b} + {\frac{{dist}\; 1206\; b}{{{dist}\; 1206\; a} + {{dist}\; 1206\; b}}*{length}\; 1206\; a}}$

The distance between the point and the flood elevation line may equalthe shortest distance between the initial elevation point 1223 c and theflood elevation line. Other distances are also contemplated.

In some embodiments, the slope of the temporary line (slope_temp) may bedetermined as follows (with slope of flood elevation line 1206a=slope1206 a and slope of flood elevation line 1206 b=slope1206 b):

${slope\_ temp} = {{\frac{{dist}\; 1206\; a}{{{dist}\; 1206\; a} + {{dist}\; 1206\; b}}*{slope}\; 1206\; b} + {\frac{{dist}\; 1206\; b}{{{dist}\; 1206\; a} + {{dist}\; 1206\; b}}*{slope}\; 1206\; a}}$

Other methods of determining ratios for slopes and/or lengths are alsopossible. The temporary line may be drawn using the calculated slope andlength. The elevation points on the other side of the flood elevationline may then be searched for an elevation point approximately the sameas the initial elevation point 1223 c. The flood elevation line 1206 cfrom the initial elevation point 1223 c to the determined elevationpoint 1223 g may then replace the temporary line. The flood elevationline 1206 c may be assigned an elevation approximately equal to theaverage of the initial elevation point 1223 c and the determinedelevation point 1223 g.

In some embodiments, other flood elevation line creation methods may beused. In some embodiments, combinations of the methods described hereinmay be used.

FIG. 13 illustrates an embodiment of approximating a flood elevation fora point 1341 between two flood elevation lines (e.g., BFE lines 1306a,b) for the 100-year flood boundaries 1001. The property point 1341 maybe a specific property, a geocoded point location, or a point ofinterest (POI). In some embodiments, a substantially perpendicular line1306 c may be formed, on the digital elevation map, between the propertypoint 1341 and a flood source line feature (e.g., centerline 1007) of aflood source in a same catchment area as the property point 1341. Tocalculate the flood elevation for the point 1341 between two BFE lines1306 a,b, distances 1351 a,b may be calculated between the BFEs 1306 a,band the substantially perpendicular line 1306 c. In some embodiments,distances 1351 a,b may be calculated between the BFEs 1306 a,b and thepoint 1341 (e.g., a shortest distance between the point 1341 and the BFEor a distance along a line on a right angle to the BFE and through thepoint 1341). In some embodiments, based on the distances 1351 a,b, anelevation between the two BFEs 1306 a,b may be extrapolated for thepoint 1341. For example, if BFE 1306 a is 200 ft, BFE 1306 b is 210 ft,distance 1351 a (dist1351 a) is 100 ft and distance 1351 b (dist1351 b)is 200 ft (totaldist=300 ft), the BFE for 1341 may be calculated asfollows:

${BFE} = {{\frac{{dist}\; 1351\; b}{totaldist}*{BFE}\; 1306\; a} + {\frac{{dist}\; 1351\; a}{totaldist}*{BFE}\; 1306\; b}}$${BFE} = {{{\frac{200}{300}*200\mspace{14mu} {ft}} + {\frac{100}{300}*210\mspace{14mu} {ft}}} = {{{133.33\mspace{14mu} {ft}} + {70\mspace{14mu} {ft}}} = {203.33\mspace{14mu} {ft}}}}$

Therefore, the BFE 1306 c may be 203.33 ft (which may be rounded to 203ft). Other methods of calculating a weighted average for the BFE 1306 cfor point 1341 are also contemplated. In some embodiments, at least twopoints of flood frequency versus flood elevation for the property pointmay be calculated by determining the flood elevation for the point attwo flood frequencies (e.g., by approximating a flood elevation for theproperty point between two flood elevation lines for the 100 year floodzone and two flood elevation lines for the 500 year flood zone). In someembodiments, the substantially perpendicular line 1306 c may be asubstantially perpendicular cross section through the property point.

FIG. 14 illustrates an embodiment of approximating a flood elevationline for a property point 1441 between two flood elevation lines (e.g.,flood elevation lines 1406 a,b) for the 500-year flood boundaries 1003.In some embodiments, a substantially perpendicular line 1406 c may beformed, on the digital elevation map, between the property point 1441and a flood source line feature (e.g., centerline 1007) of a floodsource in a same catchment area as the property point 1441. To calculatethe flood elevation line for a property point 1441 between two floodelevation lines 1406 a,b, distances 1451 a,b may be calculated betweenthe flood elevation lines 1406 a,b and the substantially perpendicularline 1406 c. In some embodiments, distances 1451 a,b may be calculatedbetween the flood elevation lines 1406 a,b and the property point 1441.In some embodiments, based on the distances 1451 a,b, an elevationbetween the two flood elevation lines 1406 a,b may be extrapolated forthe property point 1441. For example, if flood elevation line 1406 a(FE_1406 a) is 240 ft, flood elevation line 1406 b (FE_1406 b) is 250ft, distance 1451 a (dist1451 a) is 250 ft and distance 1451 b (dist1451b) is 50 ft (totaldist=300 ft), the flood elevation for 1441 (FE_1441)may be calculated as follows:

$\mspace{79mu} {{{FE\_}1441} = {{\frac{{dist}\; 1451\; b}{totaldist}*{FE\_}1406\; a} + {\frac{{dist}\; 1451\; a}{totaldist}*{FE\_}1406\; b}}}$${{FE\_}1441} = {{{\frac{50}{300}*240\mspace{14mu} {ft}} + {\frac{250}{300}*250\mspace{14mu} {ft}}} = {{{40\mspace{14mu} {ft}} + {208.33\mspace{14mu} {ft}}} = {248.33\mspace{14mu} {ft}}}}$

Therefore, the flood elevation line 1406 c may be 248.33 ft (which maybe rounded to 248 m). Other methods of calculating a weighted averageFor the flood elevation line 1406 c are also contemplated. In someembodiments, flood elevation line 1406 c may be formed as asubstantially perpendicular line 1306 c or a substantially perpendicularcross section through the property point 1441.

FIG. 15 illustrates another embodiment for calculating a flood elevationline for a property point between two flood elevation lines. In someembodiments, distances 1551 a and 1551 b between property point 1541 andthe nearest flood elevation lines (e.g., flood elevation lines 1506a,b). The property point 1541 may be a specific property, a geocodedpoint location, or a point of interest (POI). Distances 1551 a and 1551b may be used to place a dummy point 1543 between the 100-year floodboundary flood elevation lines on the centerline 1007. If the centerline1007 does not exist, a dummy point may be placed between the two middlepoints 1577 a,b of the flood elevation lines 1506 a,b. Other locationsfor the dummy point are also contemplated. Distances 1551 a,b may be theshortest distance between the property point 1541 and the nearest pointon the flood elevation lines 1506 a,b or a distance along a line on aright angle to the flood elevation lines 1506 a,b and through theproperty point 1541. A ratio of the relative distances may be used toplace the dummy point 1543. For example (distance to 1551 a=dist1551 a;distance to 1551 b=dist1551 b; distance to 1555 a=dist1555 a; totaldistance between 1577 a and 1577 b=tot_dist1553; and distance to 1555b=dist1555 b):

${{dist}\; 1555\; a} = {\frac{{dist}\; 1551\; a}{{{dist}\; 1551\; a} + {{dist}\; 1551\; b}}*{tot\_ dist}\; 1553}$${{dist}\; 1555\; b} = {\frac{{dist}\; 1551\; b}{{{dist}\; 1551\; a} + {{dist}\; 1551\; b}}*{tot\_ dist}\; 1553}$

The 100-year flood elevation line for the dummy point 1543 may then becalculated using the nearest flood elevation lines for the 100-yearflood boundary 1001 using the method as seen in FIG. 13. This 100-yearflood boundary flood elevation line may then be used for the propertypoint 1541.

FIG. 16 illustrates an embodiment of determining a flood elevation linefor a property point outside of the 500-year flood boundary 1003. Insome embodiments, the nearest flood elevation lines (e.g., floodelevation lines 1606 a,b) may be extended past the property point 1641by extending their lines along the directions of the respective lines.The nearest distances 1651 a,b to each extended flood elevation line maybe calculated (e.g., a shortest distance between the property point 1641and the flood elevation line or a distance along a line on a right angleto the flood elevation line and through the property point 1641) andused to place a dummy point 1643 on the centerline 1007 (or between themiddle points 1677 a,b of two flood elevation lines 1606 a,b). Forexample, the relative distances 1655 a,b may be calculated based on thedistances 1651 a,b. The 100-year flood boundary flood elevation line forthe dummy point 1643 may then be calculated using the nearest floodelevation lines for the 100-year flood boundary 1001 using the method asseen in FIG. 13. This 100-year flood boundary flood elevation line maythen be used for the property point 1641.

In some embodiments, substantially seamless national coverage (and/orglobal coverage) for 100-year and 500-year flood elevation lines (and/orother flood elevation frequencies) and flood boundaries may bedetermined using the methods described herein. The flood frequencyversus flood loss curve may be derived based on the computed floodfrequency versus flood elevation curve, digital elevation datasets,and/or collected damage curves at a property point, a geocoded point ora point of interest (POI). In some embodiments, triangulated irregularnetwork (TIN) surfaces may be created using the determined floodelevation lines and flood zone boundaries. The TIN surfaces may then berecomputed when FEMA DFIRM datasets are updated. In some embodiments,once a flood elevation line is established for a property point, the100-year flood elevation line and 500-year flood elevation line for theproperty point (or elevations of the flood at other flood frequencymarks) may be used as points on a flood frequency versus flood elevationcurve. These points may also be used with a probability distribution(e.g., the Log Pearson Type III distribution, the Log Normaldistribution, and/or the Extreme Value Type I distribution as describedabove) to calculate other points on the curve. Once the curve iscalculated, the flood elevation at other flood frequencies may bedetermined (e.g., flood elevation at the 2 year, 10 year, 50 year,100-year, 200 year, 500-year, and 1000 year).

Once the flood frequency versus flood elevation curve is calculated, aflood frequency versus damage curve may be created. Users may enter thetotal value of property at the property point (e.g., commercialproperty) and associated property characteristics (e.g., property type).A ground elevation may be determined at the property point (e.g., usingthe DEM data) and the latitude/longitude of the property point. Theflood depths for the property point may be calculated by subtracting theground elevation of the property point from the flood elevations duringdifferent flood frequency floods. For example:

flood elevation=flood depth−ground elevation of the property point

where flood depth may equal the depth of the flood water above theground at the property point (flood elevation may be the elevation ofthe flood water surface above sea level). If flood depths is negative, a0 may be used. This data may be entered in a chart and/or plot (e.g.,see FIG. 17 a). A damage curve may also be determined or provided by auser (e.g., using the building type) (e.g., see FIG. 17 b). Using thedata from the flood frequency versus flood elevation table (FIG. 17 a),the flood damage curve (FIG. 17 b), and the property value, the floodfrequency versus flood damage curve (FIG. 17 c) can be calculated. Forexample:

Flood damage at flood frequency=total property point value*% of Damageat the related flood depth

In some embodiments, this information may be used to calculate theaverage annual loss for the property point. For example:

average annual loss for the property point=SUM(probability that a floodevent occurs*the associated loss

where SUM may be a summation over several flood events. FIG. 17 d alsoshows a relationship between calculated loss value and flood frequency.FIG. 18 a illustrates an embodiment of a distribution for average annualloss and FIG. 18 b illustrates an embodiment of a chart calculating anaverage annual loss. Sample average annual loss 1801 is shown as a lineon the annual aggregate loss with a standard deviation 1803. Theprobable maximum loss may equal the maximum associated loss for theproperty point due to flood (e.g., $3,345,000). This may represent thelargest economic loss likely to occur for a given policy or a set ofpolicies when a catastrophic flood event occurs. For a commercialproperty, this may represent an estimate of the largest loss that abuilding or a business in the building is likely to suffer. In someembodiments, the potential premium for the property point may equal theaverage annual loss plus a risk load plus an expense load where the riskload may be a number representing the uncertainty of the average annualloss (e.g., risk of damage to a levee or dam, inaccuracy in the floodmodel, etc.). The expense load may equal the expenses of administering aflood insurance program and other fees.

In some embodiments, an adjustment rate may be calculated to adjust theaverage annual loss by an adjustment rate representative of otherfactors. For example:

adjusted average annual loss=average annual loss*(1+adjustment rate)

In some embodiments, several different associated adjustment scores maybe used to adjust the average annual loss. In some embodiments, a capmay be applied to the adjustment scores. For example,

adjusted average annual loss=average annual loss*(1+adjustmentcap*sum(associated adjustment scores)/maximum possible sum of theadjustment scores)

As an example (e.g., as seen in FIG. 19), the risk scores may beassigned as follows: if the property point is impacted by 2-10 yearflood, the risk score may be 6.0 (there may be some repetitive lossassociated with the property point); if the property point is impactedby 10-50 year flood, the risk score may be 5.0 (there may be somepotential repetitive loss associated with the property point); if theproperty point is impacted by 50-100-year flood, the risk score may be4.0; if the property point is impacted by 100-200 year flood, the riskscore may be 3.0; if the property point is impacted by 200-500-yearflood, the risk score may be 2.0; if the property point is impacted by500-1000 year flood, the risk score may be 1.0; if the property point isnot impacted by flood, the risk score may be 0. Other risk scores arealso possible. Other risk adjustments are also contemplated. Forexample, if the property point could be impacted by damage to a levee,add 1.0 to the total risk score (the probability of damage to a leveecould increase the overall possibility of flooding); if the propertypoint could be impacted by damage to a dam, add 0.5 to the total riskscore (the probability of damage to a dam could increase the overallpossibility of flooding); if the property point could be impacted byhurricanes, add 1.0 to the total risk score; if the property point couldbe impacted by a landslide, add 0.5 to the total risk score; if theproperty point could be impacted by a tsunami, add 0.5 to the total riskscore; if the property point could be impacted by flash flooding, add0.5 to the total risk score. Other risk adjustments are also possible.In some embodiments, the adjustment rate may equal the risk scoredivided by 10. Other risk scores and divisors are also contemplated. Insome embodiments, the risk scores and adjustment rates may be modifiable(e.g., by an insurance company).

In some embodiments, a system may be provided to perform one or moremethods described herein. The system could be a web-based system thatintegrates multiple geospatial datasets, flood damage computation, andthe flood risk rating. The system may generate a flood risk assessmentreport with commercial property information, including a property pointaddress and company information. The report may further include the100-year and 500-year flood determination, a FEMA flood zone map, groundelevation of the commercial building, property point values (includingcontents, equipment, etc.) for the commercial building, flood frequencyversus flood elevation curve, flood frequency versus flood loss curve,average annual loss, probable maximum loss, flood risk rating,historical hazard events for the property point, and a reporting date.The report may be delivered to a client through a web service (e.g.,through Extensible Mark-up Language (XML)).

FIG. 20 illustrates an embodiment of a method for calculating theaverage annual loss due to flooding at a property point. It should benoted that in various embodiments of the methods described below, one ormore of the elements described may be performed concurrently, in adifferent order than shown, or may be omitted entirely. Other additionalelements may also be performed as desired.

At 2001, at least two points of flood frequency versus flood elevationfor the property point may be calculated. These points may be derived,for example, from flood elevation lines on a flood map, from derivedflood elevation lines on the flood map (e.g., derived from pre-existingflood elevation lines on the flood map), and/or gage station data nearthe property point.

At 2003, the at least two points may be used to calculate a firstplurality of points (e.g., a curve) on a distribution of flood frequencyversus flood elevation for the property point. For example, if floodelevation data exists for flood elevation lines on the 100-year floodboundary (frequency=0.01) and the 500-year flood boundary(frequency=0.002), this information may be used to calculate thedistribution of flood frequency versus flood elevation for the propertypoint. In some embodiments, the Log Pearson Type III distribution, theLog Normal distribution, and/or the Extreme Value Type I distributionmay be used. Other distributions may also be used.

At 2005, the first plurality of points may be used to calculate a secondplurality of points (e.g., a curve) on a distribution of flood frequencyversus flood damage for the property point.

At 2007, an average annual loss may be calculated for the property pointbased on the second plurality of points on the flood frequency versusflood damage distribution for the property point (e.g., see FIG. 18 b).Calculating the average annual loss may include weighting the calculatedaverage annual loss with a risk score determined for the property point.For example, the risk score may be at least partially dependent on theflood frequency of flooding at the property point or whether theproperty point may be impacted by damage to a levee, damage to a dam, ahurricane, a storm surge, a landslide, a tsunami, or a flash flood. Insome embodiments, the risk scores may be adjustable to increase ordecrease the relative effect on the annual average loss of the riskscores. The effect of the risk scores may also be capped.

FIG. 21 illustrates an embodiment of a method for using flood elevationdata to calculate a distribution for flood frequency versus floodelevation. It should be noted that in various embodiments of the methodsdescribed below, one or more of the elements described may be performedconcurrently, in a different order than shown, or may be omittedentirely. Other additional elements may also be performed as desired.

At 2101, flood elevation data may be calculated for two points on aflood frequency versus flood elevation distribution.

At 2103, the parameters for a flood distribution curve may be determinedusing the flood elevation data for the two points. The flooddistribution may be selected from the Log Pearson Type III distribution,the Log Normal distribution, or the Extreme Value Type I distribution.Other distributions may also be used.

At 2105, other points on the flood frequency versus flood elevationcurve may be calculated using the distribution.

At 2107, the flood frequency versus flood elevation curve may bedisplayed.

FIG. 22 illustrates an embodiment of a method for forming a floodelevation line by aligning elevations on a flood boundary (e.g., seeFIG. 7 a). It should be noted that in various embodiments of the methodsdescribed below, one or more of the elements described may be performedconcurrently, in a different order than shown, or may be omittedentirely. Other additional elements may also be performed as desired.

At 2201, a flood map may be overlaid on a digital elevation map. Forexample, the flood map and the digital elevation map may be aligned(e.g., geographically aligned).

At 2203, elevations for a plurality of points (e.g., elevation points609) may be determined along at least two opposing lines of a floodboundary (e.g., 100-year flood boundary 601) on the flood map.

At 2205, a point along one line of the at least two opposing lines maybe connected with a point on the opposing line. The points may notactually be on the opposing lines, but may be near the opposing lines.The two connected points may be approximately the same elevation. Insome embodiments, a line connecting the two points may be substantiallyperpendicular to the flood source line feature (e.g., centerline 607).In some embodiments, the points may not be physically connected with aline, but may instead be connected by association with each other (e.g.,in a database).

FIG. 23 illustrates an embodiment of a method for forming a floodelevation line based on pre-existing flood elevation lines (e.g., seeFIG. 12). It should be noted that in various embodiments of the methodsdescribed below, one or more of the elements described may be performedconcurrently, in a different order than shown, or may be omittedentirely. Other additional elements may also be performed as desired.

At 2301, a flood map may be overlaid on a digital elevation map. Theflood map may have at least two pre-existing flood elevation lines(which may be BFEs) for a flood boundary.

At 2303, elevations for a plurality of points along at least twoopposing lines 1003 a,b of the flood boundary and between the at leasttwo pre-existing flood elevation lines (e.g., flood elevation lines 1206a,b) may be determined. The plurality of points on a line of the floodboundary may be approximately equally spaced vertically based on theslope of the two pre-existing flood elevation lines. For example, theslope may be calculated as the upstream flood elevation (correspondingto the upstream flood elevation line such as flood elevation line 1206a)−downstream flood elevation (corresponding to the downstream floodelevation line such as flood elevation line 1206 b)/the distance betweenthe intersection of the upstream flood elevation line and the centerline1007 and the intersection of the downstream flood elevation line and thecenterline 1007. The slope may thus provide change inelevation/distance. The plurality of points may thus be equally spaced(e.g., along opposing lines 1003 a,b which may or may not be present) atequal increments of slope. For example, if the slope is 100 m/2000 m, 9points may be distributed along a flood boundary every 10 m/200 m (withan approximate 10 m change in elevation between points and the pointsapproximately spaced 200 m apart).

At 2305, a first point 1223 c on one of the at least two opposing lines(e.g., flood boundary line 1003 a) of the flood boundary may beselected.

At 2307, a second point 1223 g with approximately the same elevation onthe opposing line (e.g., flood boundary line 1003 b) may be selected.The second point 1223 g may include a point placed on the opposing lineat 2303. For example, if the first point 1223 c is the third next point(as placed at 2303) on one of the opposing lines, the second point 1223g may be the third next point (as placed in 2303) on the other opposingline. In some embodiments, the second point 1223 g may be searched forsuch that a line passing through the first point 1223 c and a region ofthe second point 1223 g may have a slope associated with at least one ofthe slopes of the pre-existing flood elevation lines (e.g., the slopebetween the first point 1223 c and the second point 1223 g may beapproximately the same slope as a pre-existing flood elevation line ormay be a weighted slope (e.g., using the distance from the first point1223 c to each of the two pre-existing flood elevation lines and theslopes of each of the two pre-existing flood elevation lines)). In someembodiments, the second point 1223 g may be searched for such that aline passing through the first point 1223 c and a region of the secondpoint 1223 g may be substantially perpendicular to the centerline 1007(at the point the line intersects the centerline 1007).

At 2309, the first point 1223 c and the second point 1223 g may beconnected to form another flood elevation line 1206 c.

FIGS. 24 a-b illustrate an embodiment of a method for forming a rastersurface (e.g., see FIG. 9) based on flood elevations. It should be notedthat in various embodiments of the methods described below, one or moreof the elements described may be performed concurrently, in a differentorder than shown, or may be omitted entirely. Other additional elementsmay also be performed as desired.

At 2401, a digital elevation map of a region (e.g., an area to bemodeled) may be provided.

At 2403, a determination may be made as to whether an area to be modeledhas line features and associated flood elevation values from the100-year flood boundary.

At 2405, if the area has line features and associated flood elevationvalues from the 100-year flood boundary, the flood elevation lines andassociated flood elevation values from the 100-year flood boundary maybe provided as input for a surface model (such as a TIN surface) tocreate a raster surface.

At 2407, if the area does not have flood elevation lines and associatedflood elevation values from the 100-year flood boundary, a determinationmay be made as to whether the area has 100-year flood boundaries.

At 2409, if the area has 100-year flood boundaries, the 100-year floodboundaries may be overlaid on top of the digital elevation data (e.g.,overlaid on the digital elevation map), and at 2411, points on the100-year flood boundary lines (e.g., the point elevations) from thedigital elevation data may be used as inputs for the surface model tocreate the raster surface for the 100-year flood elevations.

At 2413, if the area does not have 100-year flood boundaries, USGS gagedata may be used along with an HH study or USGS national flood frequencycurves (NFF) to obtain 100-year flood elevations at a location or area.At 2415, this data may be combined with known 100-year flood elevations(e.g., downstream or upstream) and used as input for the surface modelto create the raster surface 901 for 100-year flood elevations.

At 2417, a determination may be made as to whether the area has 500-yearflood boundaries.

At 2419, if the area has 500-year flood boundaries, the 500-year floodboundaries may be overlaid on top of the digital elevation data (e.g.,overlaid on the digital elevation map), and at 2421, points on the500-year flood boundary lines (e.g., the point elevations) from thedigital elevation data may be used as inputs for the surface model tocreate the raster surface for the 500-year flood elevations.

At 2423, if the area does not have 500-year flood boundaries, USGS gagedata may be used along with an HH study or USGS national flood frequencycurves (NFF) to obtain 500-year flood elevations at a location or area.At 2425, this data may be combined with known 500-year flood elevations(e.g., downstream or upstream) and used as input for the surface modelto create the raster surface 901 for 500-year flood elevations.

FIG. 25 illustrates an embodiment of a method for forming a floodelevation line (e.g., a BFB) and/or a flood boundary based on gagestation data (e.g., see FIGS. 8 a-b). In some embodiments, if the100-year flood boundaries and/or the 500-year flood boundaries are notprovided, gage station data may be used to form one or more of theseboundaries. This data may also be used to provide corresponding floodelevation lines. It should be noted that in various embodiments of themethods described below, one or more of the elements described may beperformed concurrently, in a different order than shown, or may beomitted entirely. Other additional elements may also be performed asdesired.

At 2501, a digital elevation map of a region may be provided.

At 2503, gage station data over time for at least one gage station inthe region may be provided (e.g., see gage station data in FIG. 38 b).In some embodiments, a USGS map (e.g., a USGS Hydrologic Unit Code Map)may be used to determine the hydraulic unit code for the region (e.g.,by entering a geocoded point for the region or address). The gagestations assigned to that hydraulic unit code may then be used.

At 2505, a curve for flood frequency versus flood elevation may bedetermined for the region using the gage station data and the digitalelevation map. For example, a statistical and hydrologic analysis may beapplied to data from the indicated gage station(s). (As another example,see FIG. 38 b and accompanying description above).

At 2507, at least one flood elevation line and/or flood boundary for theregion may be determined using the determined flood frequency versusflood elevation curve. For example, the 100-year flood elevation line(corresponding to the determined 100 year flood elevation for a propertypoint in the region) and/or the 500-year flood elevation line(corresponding to the determined 500 year flood elevation for theproperty point) may be provided for a property point by using thedetermined flood frequency versus flood elevation curve. In someembodiments, several flood elevation lines may be used to construct thecorresponding flood boundary (e.g., by connecting the adjacent ends ofcorresponding flood elevation lines to form corresponding floodboundaries).

FIG. 26 illustrates an embodiment of a method for forming a floodelevation line by extending a pre-existing flood elevation line (e.g.,forming a 500-year flood elevation line by extending a BFE) (e.g., seeFIG. 10). It should be noted that in various embodiments of the methodsdescribed below, one or more of the elements described may be performedconcurrently, in a different order than shown, or may be omittedentirely. Other additional elements may also be performed as desired.

At 2601, a flood map with a flood elevation line 1005 a for a firstflood boundary 1001 (e.g., a BFE 1005 a for a 100-year flood boundary1001) may be overlaid on a digital elevation map.

At 2603, elevations for a plurality of points along a first line 1003 aand a second, opposing, line 1003 b of a second flood boundary (e.g.,opposing lines of the second flood boundary 1003) may be determined.

At 2605, the flood elevation line 1005 a may be extended to theplurality of points along the first line 1003 a. The flood elevationline 1005 a may be extended along approximately the same direction asthe flood elevation line (e.g., a BFE) for the first flood boundary.

At 2607, a first point may be selected approximately located on anintersection of the extended flood elevation line 1006 a and the floodboundary 1003 (e.g., comprised of a plurality of points along the firstline). The elevation value may be taken from the digital elevationdataset at the intersection point. For example, the closer of points1023 a or 1023 d to intersection point 1033 a may be used. In someembodiments, a point at intersection 1033 a may be used as the firstpoint.

At 2609, a second point may be selected with an elevation approximatelyequal to an elevation of the first point. The second point may beapproximately at an intersection of the extended flood elevation line1006 a and the plurality of points along the second line 1003 b. Thesecond point may be chosen to have an elevation approximately equal tothe first point elevation. For example, the point (between either point1023 c or 1023 d) with the closest elevation to the first point may beselected as the second point.

At 2611, a flood elevation line 1006 a for the second flood boundary1003 may be formed between the first point and the second point.

At 2613, the flood elevation line for the second flood boundary may beassigned an elevation approximately equal to an average elevation of thefirst point and the second point.

FIG. 27 illustrates an embodiment of a method for forming a floodelevation line by using a centerline (e.g., see FIG. 11). It should benoted that in various embodiments of the methods described below, one ormore of the elements described may be performed concurrently, in adifferent order than shown, or may be omitted entirely. Other additionalelements may also be performed as desired.

At 2701, a flood map with a centerline 1007 may be overlaid on a digitalelevation map.

At 2703, elevations for a plurality of points along a first line 1003 aand a second, opposing, line 1003 b of a first flood boundary 1003 maybe determined.

At 2705, a flood elevation line 1105 a may be formed from a startingpoint on the centerline 1007 to a first plurality of points along thefirst line 1003 a. The flood elevation line 1105 a may be formedsubstantially perpendicular to the centerline 1007 at the starting pointon the centerline 1007.

At 2707, the flood elevation line 1105 a may be extended from thestarting point on the centerline 1007 to a second plurality of pointsalong the second line 1003 b. The flood elevation line 1105 a may beextended substantially perpendicular to the centerline 1007 at thestarting point on the centerline 1007. For example, the flood elevationline 1105 a may be substantially perpendicular to the centerline 1007 atthe location where the flood elevation line 1105 a crosses thecenterline 1007.

At 2709, a first point may be selected approximately located on anintersection of the flood elevation line 1105 a and flood boundary 1003(e.g., the plurality of points along the first line 1003 a).

At 2711, a second point may be selected with an elevation approximatelyequal to an elevation of the first point. The second point isapproximately at an intersection of the extended flood elevation line1105 a and the second plurality of points (e.g., along second line 1003b).

At 2713, the flood elevation line 1105 a for the first flood boundary1003 may be reformed between the first point and the second point.

At 2715, the flood elevation line 1105 a may be assigned an elevationapproximately equal to an average elevation of the first point and thesecond point.

FIG. 28 illustrates an embodiment of a method for using two perimeterflood elevation lines for forming subsequent intermediary floodelevation lines (e.g., see FIG. 12). It should be noted that in variousembodiments of the methods described below, one or more of the elementsdescribed may be performed concurrently, in a different order thanshown, or may be omitted entirely. Other additional elements may also beperformed as desired.

At 2801, a flood map may be overlaid on a digital elevation map.

At 2803, a first flood elevation line 1206 a and a second floodelevation line 1206 b may be selected. In some embodiments, the firstflood elevation line 1206 a may be an upstream flood elevation line andthe second flood elevation line 1206 b may be a downstream floodelevation line. The first flood elevation line 1206 a and the secondflood elevation line 1206 b may intersect respective flood boundaries.For example, the first flood elevation line 1206 a may intersect theleft flood boundary 1003 a at point 1223 a and the right flood boundary1003 b at point 1223 b. The second flood elevation line 1206 b mayintersect the left flood boundary 1003 a at point 1223 e and the rightflood boundary 1003 b at point 1223 f.

At 2805, the first slope with respect to the left flood boundary 1003 amay be calculated. For example, the slope may be calculated as theupstream flood elevation (corresponding to the upstream flood elevationline 1206 a)−downstream flood elevation (corresponding to the downstreamflood elevation line 1206 b)/the distance between point 1223 a and 1223e (distance along the left flood boundary line 1003 a). The slope maythus provide change in elevation/distance corresponding to the leftflood boundary line 1003 a.

At 2807, the second slope with respect to the right flood boundary 1003b may be calculated. For example, the second slope may be calculated asthe upstream flood elevation (corresponding to the upstream floodelevation line 1206 a)−downstream flood elevation (corresponding to thedownstream flood elevation line 1206 b)/the distance between point 1223b and 1223 f (distance along the right flood boundary line 1003 b). Theslope may thus provide change in elevation/distance corresponding to theright flood boundary line 1003 b.

At 2809, using the first slope, a plurality of points may be distributedalong the left flood boundary 1003 a. The plurality of points may beequally spaced along the left flood boundary 1003 a at equal incrementsof slope. For example, if the slope is 100 m/2000 m (flood elevationchange/distance), 9 points may be distributed along the left floodboundary 1003 a every 10 m/200 m (with an approximate 10 m change inelevation between points and the points approximately spaced 200 mapart).

At 2811, using the second slope, a plurality of points may bedistributed along the right flood boundary 1003 b. The plurality ofpoints may be equally spaced along the right flood boundary 1003 b atequal increments of slope. For example, if the slope is 120 m/2200 m(flood elevation change/distance), 9 points may be distributed along theright flood boundary 1003 b every 12 m/220 m (with an approximate 10 mchange in elevation between points and the points approximately spaced200 m apart).

At 2813, a first point 1223 c on one of the flood boundaries (e.g., theleft flood boundary 1003 a) may be selected.

At 2815, a second point 1223 g with approximately the same elevation onthe other flood boundary (e.g., the right flood boundary 1003 b) may beselected. The second point 1223 g may include a point placed on theboundary line at 2811. For example, if the first point 1223 c is thethird next point (as placed at 2809) on the left flood boundary 1003 a,the second point 1223 g may be the third next point (as placed in 2811)on the other opposing line (e.g., right flood boundary 1003 b). In someembodiments, the second point 1223 g may be searched for such that aline passing through the first point 1223 c and a region of the secondpoint 1223 g may have a slope associated with at least one of the slopesof the pre-existing flood elevation lines (e.g., the slope between thefirst point 1223 c and the second point 1223 g may be approximately thesame slope as a pre-existing flood elevation line or may be a weightedslope (e.g., using the distance from the first point 1223 c to each ofthe two pre-existing flood elevation lines and the slopes of each of thetwo pre-existing flood elevation lines)). In some embodiments, thesecond point 1223 g may be searched for such that a line passing throughthe first point 1223 c and a region of the second point 1223 g may besubstantially perpendicular to the centerline 1007.

At 2817, the first point 1223 c may be connected to the second point1223 g to form another flood elevation line 1206 c.

In some embodiments, elevations for a plurality of points along at leasttwo opposing lines of a flood boundary may be determined (the points ofthe plurality of points on a line of the flood boundary may beapproximately equally spaced between the first and second floodelevation lines 1206 a,b (e.g., BFEs)). A first flood elevation line1206 a (having a first slope) may be formed by connecting a first point1223 a along one line of the at least two opposing lines with a secondpoint 1223 b on the opposing line. The first point 1223 a and secondpoint 1223 b may be approximately the same elevation. A second floodelevation line 1206 b (having a second slope) may be formed byconnecting a third point 1223 e along one line of the at least twoopposing lines with a fourth point 1223 f on the opposing line. Thethird point 1223 e and fourth point 1223 f may be approximately the sameelevation. The elevations for a plurality of points along the at leasttwo opposing lines of the flood boundary and between the first andsecond flood elevation lines may be determined. In some embodiments, theelevations may be displayed. A fifth point 1223 c may be selected on oneof the at least two opposing lines. In some embodiments, a sixth point1223 g with approximately the same elevation on the opposing line may besearched for such that a line passing through the fifth point 1223 c anda region of the sixth point 1223 g may have approximately a slope(weighted_slope) equal to a sum of a weighted value of the first slopeplus a weighted value of the second slope. The weighted values of thefirst slope and the second slope may depend on their proximity to thefifth point 1223 c. For example, the weighted_slope may calculated asfollows (where dist_sec_elev=distance from the second flood elevationline and dist_first_elev=distance from the first flood elevation line):

${weighted\_ slope} = {{\frac{{dist\_ sec}{\_ elev}}{{{dist\_ first}{\_ elev}} + {{dist\_ sec}{\_ elev}}}*{first\_ slope}} + {\frac{{dist\_ first}{\_ elev}}{{{dist\_ first}{\_ elev}} + {{dist\_ sec}{\_ elev}}}*{sec\_ slope}}}$

FIG. 29 illustrates an embodiment of a method for forming a floodelevation line for a property point between two pre-existing base floodelevation lines (e.g., see FIG. 13). A flood elevation line through aproperty point may provide at least one point of flood frequency versusflood elevation. For example, the flood elevation line through theproperty point may correspond to a flood frequency (e.g., a 100 yearflood elevation line through the property point) and may have a floodelevation associated with the flood elevation line. For example, a floodelevation line of 180 m (with each endpoint intersecting the 100 yearflood boundary at the 180 m elevation) through the property point maycorrespond to a flood elevation of 180 m for the property point for aflood frequency of once every 100 years (0.01) for the property point.It should be noted that in various embodiments of the methods describedbelow, one or more of the elements described may be performedconcurrently, in a different order than shown, or may be omittedentirely. Other additional elements may also be performed as desired.

At 2901, a flood map, with a first flood elevation line 1306 a with afirst flood elevation and a second flood elevation line 1306 b with asecond flood elevation, may be overlaid on a digital elevation map.

At 2903, a property point 1341 may be provided between the first floodelevation line 1306 a and the second flood elevation line 1306 b.

At 2905, a first distance 1351 a between the property point 1341 and thefirst flood elevation line 1306 a may be determined.

At 2907, a second distance 1351 b between the property point 1341 andthe second flood elevation line 1306 b may be determined.

At 2909, a property point flood elevation approximately equal to aweighted average of the first flood elevation (first_elev) and thesecond flood elevation (sec_elev) may be determined. For example, if atotal distance (total_dist) approximately equals the first distance(first_dist) plus the second distance (sec_dist), the weighted average(avg) for the property point flood elevation may be determined asfollows:

${avg} = {{( \frac{first\_ dist}{total\_ dist} )*{sec\_ elev}} + {\frac{sec\_ dist}{total\_ dist}{first\_ elev}}}$

Where avg=flood elevation for the property point 1341 (and,correspondingly, for a flood elevation line 1306 c passing through theproperty point 1341.

FIG. 30 illustrates an embodiment of a method for forming a floodelevation line for a property point using two pre-existing floodelevation lines (e.g., see FIG. 15). It should be noted that in variousembodiments of the methods described below, one or more of the elementsdescribed may be performed concurrently, in a different order thanshown, or may be omitted entirely. Other additional elements may also beperformed as desired.

At 3001, a flood map may be overlaid on a digital elevation map. In someembodiments, the flood map may include a first flood elevation line 1506c and a second flood elevation line 1506 d for a first flood boundary1001 (e.g., BFEs for a 100-year flood boundary) and a third floodelevation line 1506 a and a fourth flood elevation line 1506 b for asecond flood boundary 1003 (e.g., flood elevation lines for a 500 yearflood boundary).

At 3003, a property point 1541 may be provided between the third floodelevation line 1506 a and the fourth flood elevation line 1506 b.

At 3005, a first distance 1551 a between the property point 1541 and thethird flood elevation line 1506 a may be determined.

At 3007, a second distance 1551 b between the property point 1541 andthe fourth flood elevation line 1506 b may be determined.

At 3009, a flood elevation for the property point 1541 relative to thefirst flood boundary 1001 may be determined as approximately equal to aweighted average of the first flood elevation (first_elev) (e.g., of thefirst flood elevation line 1506 c) and the second flood elevation(sec_elev) (e.g., of the second flood elevation line 1506 d). Forexample, if a total distance (total_dist) approximately equals the firstdistance (first_dist) plus the second distance (seq_dist), the weightedaverage may be determined as follows:

${avg} = {{( \frac{first\_ dist}{total\_ dist} )*{sec\_ elev}} + {\frac{sec\_ dist}{total\_ dist}{first\_ elev}}}$

Where avg=flood elevation for the property point 1541 (and,correspondingly, for a flood elevation line passing through the propertypoint 1541.

In some embodiments, if the flood map includes a centerline, the methodmay further include placing a dummy point on the centerline between thefirst base flood elevation line and the second base flood elevation line(e.g., see FIG. 15). The dummy point may be placed such that a ratio ofthe distance between the dummy point and the first base flood elevationline to the distance between the dummy point and the second base floodelevation line is approximately equal to the ratio of the distancebetween the first distance to the second distance.

FIG. 31 illustrates an embodiment of a method for providing a flood riskassessment for a point. It should be noted that in various embodimentsof the methods described below, one or more of the elements describedmay be performed concurrently, in a different order than shown, or maybe omitted entirely. Other additional elements may also be performed asdesired.

At 3101, a property point may be provided.

At 3103, the property point may be geocoded (e.g., to provide an x,ycoordinate for a digital elevation and/or flood map).

At 3105, at least two flood elevation lines may be determined for thegeocoded property point (e.g., a BFE for the 100-year flood boundary anda flood elevation line for the 500-year boundary).

At 3107, a flood frequency versus flood elevation curve may bedetermined for the geocoded point using the at least two flood elevationlines.

At 3109, a flood frequency versus damage curve may be determined. Forexample, the user may provide flood elevation versus % damage and thevalue of the property point to be used with the flood frequency versusdamage curve. In some embodiments, this information may be used tocalculate the average annual loss (e.g., see FIG. 18 b).

FIG. 32 illustrates an embodiment of a web-based method for providing aflood risk assessment for a point. It should be noted that in variousembodiments of the methods described below, one or more of the elementsdescribed may be performed concurrently, in a different order thanshown, or may be omitted entirely. Other additional elements may also beperformed as desired.

At 3201, a property point may be entered into a web-based system (e.g.,the address of a targeted portfolio may be entered into a web-basedsystem). For example, the address of the property point may be enteredby a client into an (Hyper Text Markup Language) HTML page provided bythe web-based system when the client accesses the web-based system usinga URL (Uniform Resource Locator).

At 3203, the property point may be geocoded (e.g., an x,y coordinate(such as a latitude/longitude)) by the system (e.g., by a web server).

At 3205, a determination may be made as to whether the property point iswithin a 100-year flood zone, a 500-year flood zone, or neither.

At 3207, if the property point is within the 100-year flood zone and/orthe 500-year flood zone, the 100-year and 500-year flood elevations maybe determined.

At 3209, the flood frequency versus elevation curve may be determined atthe property point. In some embodiments, a plurality of points along thecurve may be determined instead of actually drawing the curve.

At 3211, a flood frequency curve versus flood loss may be determined forthe property point.

At 3213, if the property point is not within the 100-year flood zoneand/or the 500-year flood zone, the system may determine the distancesto the flood zones and the differences in flood elevations of theseflood zones to calculate a weighted average for the property point.

At 3215, the information (including flood frequency curves, distances,elevations, etc.) may be provided to a flood hazard rating engine todetermine a flood hazard rating corresponding to the information.

At 3217, the information may be used by a flood hazard rating engine toprovide a flood risk assessment report. In some embodiments, otherinformation may also be used to provide the report. The report mayinclude, for example, commercial property information, including aproperty point address and company information, the 100-year and500-year flood elevations, a FEMA flood zone map, ground elevation ofthe commercial building, property point values (including contents,equipment, etc.) for the commercial building, flood frequency versusflood elevation curve, flood frequency versus flood loss curve, averageannual loss, probable maximum loss, flood risk rating, historical hazardevents for the property point, and a reporting date. In someembodiments, the report may be provided as a downloadable file, anattachment in an email, or presented on screen for a user. Other reportformats are also possible.

In various embodiments, prior to determining at least two points offlood elevation for flood frequency, available flood boundaries and/orflood elevation lines (e.g., from a flood map) may beredefined/corrected (e.g., by aligning/redrawing the flood boundariesand/or flood elevation lines on a digital elevation map). In someembodiments, endpoints of a flood elevation line feature (e.g., a BFE)created by previous flood studies may be adjusted to a 10 m or moreaccurate digital elevation map (e.g., see FIG. 33).

FIGS. 33 a-b illustrates an embodiment of a method for correcting aflood elevation line. It should be noted that in various embodiments ofthe methods described below, one or more of the elements described maybe performed concurrently, in a different order than shown, or may beomitted entirely. Other additional elements may also be performed asdesired.

At 3301, a flood map may be aligned with a digital elevation map. Forexample, landmark features and/or set reference points may be alignedbetween the flood map and the digital elevation map (e.g., by overlayingthese points on the flood map and digital elevation map). In someembodiments, the flood map may have at least one flood elevation line3351 a with two endpoints (a first endpoint 3353 a and a second endpoint3353 b) and at least one associated flood elevation.

At 3303, an end (e.g., the first endpoint 3353 a) of the flood elevationline 3351 a may be aligned with an elevation point on the digitalelevation map with a similar elevation as the associated floodelevation. For example, the elevation may be approximately the same ormay be within a predetermined buffer distance (e.g., as set by a user).

At 3305, the other endpoint (e.g., the second endpoint 3353 b) may bemoved to a point on the digital elevation map that is collinear with theflood elevation line 3351 a and that has a similar elevation as theassociated flood elevation line 3351 a. For example, the elevation ofthe moved second endpoint may be approximately the same or may be withina predetermined buffer distance (e.g., as set by a user). In someembodiments, a straight line object 3355 a may be created using thesecond endpoint 3353 b and an adjacent point (e.g., a closest point tothe second endpoint 3353 b) in the flood elevation line 3351 a. Thestraight line object 3355 a may then be expanded or collapsed until anelevation value from the digital elevation map matches the elevationvalue of the first endpoint 3353 a. The second endpoint 3353 b may thenbe moved to the new location with the similar elevation value as thefirst endpoint 3353 a.

At 3307, several flood elevation lines for a flood frequency may bere-positioned and the corresponding flood boundary may be redrawn alongthe corrected endpoints of each side of the adjusted flood elevationlines. For example, if the corrected flood elevation lines correspond tothe 100 year flood boundary, the endpoints of the corrected floodelevation lines may be connected (on either side of the flood sourceline feature) to create an adjusted flood boundary corresponding to the100 year flood zone.

FIG. 34 illustrates an embodiment of a method for redefining at least aportion of a flood boundary. It should be noted that in variousembodiments of the methods described below, one or more of the elementsdescribed may be performed concurrently, in a different order thanshown, or may be omitted entirely. Other additional elements may also beperformed as desired.

At 3401, a first Triangulated Irregular Network (TIN) elevation surfacethat triangulates a plurality of flood elevation line endpointscorresponding to the flood frequency may be created. In someembodiments, the plurality of flood elevation lines may be pre-defined(e.g., on a flood map) or may be formed using one of the methodsdescribed herein (e.g., FIG. 33 a) to use in adjusting a flood boundary.Example TIN elevation surfaces may be seen in FIG. 36 b (e.g., see TINsurfaces 3603 and 3601). In some embodiments, the surface may be definedby connecting endpoints on either side of the flood source line feature(e.g., without necessarily triangulating all of the endpoints). As withthe other embodiments presented herein, the lines and surfaces may beactually drawn (e.g., manually and/or graphically), or may berepresented by associations formed for corresponding data points (e.g.,stored in a database). Other representations are also contemplated.

At 3403, a second Triangulated Irregular Network (TIN) elevation surfacethat triangulates a plurality of digital ground elevation points may becreated. For example, the second elevation surface may follow the groundsurface.

At 3405, the at least a portion of the flood boundary at an intersectionbetween the first TIN elevation surface and the second TIN elevationsurface may be redefined. For example, the flood boundary may be formedalong the points where the first TIN elevation surface points intersectthe second TIN elevation surface (e.g., where the flood elevation lineendpoints match the corresponding ground elevations).

FIGS. 35 a-b illustrate an embodiment of a method for correcting a floodboundary using a digital elevation map. For example, flood elevationlines may be created partially using existing flood boundaries, watersource centerlines (or flow pass), and a digital elevation map (or otherDEM dataset). This method may be used for FEMA designated “A” zoneswithout existing flood elevation lines (such as BFEs). The method mayalso be used for other areas. It should be noted that in variousembodiments of the methods described below, one or more of the elementsdescribed may be performed concurrently, in a different order thanshown, or may be omitted entirely. Other additional elements may also beperformed as desired.

At 3501, a flood elevation line may be formed, on the digital elevationmap, for flood boundary correction. For example, the flood elevationline may be formed according to methods discussed above with respect toFIGS. 6-8 b, 10-12, 14, etc.). Other flood elevation line formationtechniques are also contemplated.

At 3503, the flood boundary 3571 may be corrected by redefining at leasta portion of the flood boundary 3571 using the formed flood elevationline (e.g., see elements 3505-3513 below).

At 3505, a flood source line feature (e.g., centerline 3551) may becreated by accumulating lowest elevation points on the digital elevationmap indicative of a flow path. For example, river centerline elevationpoints (e.g., from a river centerline study area dataset or a computedflow path using a DEM dataset) may be used. Points corresponding to thelowest ground elevation points (e.g., along a line) may be connectedand/or associated with a flow path (e.g., the ground elevation pointsfor the floor of a river may be lower than ground elevation points alongthe river bank).

At 3507, a second line 3557 a may be created that is substantiallyperpendicular to the flood source line feature 3551. Again, thesubstantially perpendicular line may be actually drawn, or anappropriate association for stored data points may be stored.

At 3509, the second substantially perpendicular line 3557 a may beintersected with a flood boundary on each side of the flood source linefeature 3551 to create two intersection points (e.g., intersectionpoints 3553 a,b).

At 3511, a point 3555 may be determined that is collinear with thesecond substantially perpendicular line 3557 a on the opposite side ofthe flood source line feature 3551 that has substantially the sameelevation as the intersected point 3553 a of the at least twointersection points closest to the flood source line feature 3551.

At 3513, a flood elevation line 3557 b may be created by connecting theclosest intersected point 3553 a and the determined collinear point3555. The line may actually be drawn or stored (e.g., recording thelocation and/or elevation (for example, from the DEM)). The floodelevation line 3557 b may have a similar elevation at both endpoints3553 a, 3555.

At 3515, other flood elevation lines (e.g., 3559 a,b) may be determined(e.g., at a distance interval of 100 feet). Other distance intervals arealso contemplated.

At 3517, a TIN surface may be created using the determined floodelevations lines (e.g., by using the endpoints of the flood elevationlines to define a TIN surface for the corresponding flood frequency).

At 3519, a TIN surface may be created for the ground surface (e.g.,comprising the ground elevation points)

At 3521, the two created TIN surfaces may be intersected to createre-delineated flood boundaries (flood boundaries may occur at theintersection of the two surfaces).

FIG. 36 illustrates an embodiment of a method for determining floodfrequency versus flood elevation points using three dimensionalsurfaces. It should be noted that in various embodiments of the methodsdescribed below, one or more of the elements described may be performedconcurrently, in a different order than shown, or may be omittedentirely. Other additional elements may also be performed as desired.

At 3602, a first flood-frequency elevation surface 3601 may be defined.The flood-frequency elevation surface 3601 may be defined by respectiveelevation points of a water level during a flood at the respectivefrequency for the flood-frequency elevation surface. For example, thesurface of the water during a 100 year flood may form theflood-frequency elevation surface 3601 for the 100 year flood frequency.In some embodiments, the edges of the flood-frequency elevation surface3601 may correspond to the endpoints of the associated flood elevationlines corresponding to the designated flood frequency.

At 3604, a second flood frequency elevation surface 3603 may be defined.

At 3606, a cross-section surface 3605 may be defined that passes throughthe property point 3607 and is substantially perpendicular to a floodsource line feature (e.g., centerline 307). In some embodiments, thecross section 3605 may geospatially, hydrologically, and hydraulicallylink the property point 3607 to the flood source (e.g., centerline 307).

At 3608, the intersection points between the cross section surface 3605and the flood frequency elevation surfaces 3601 and 3603 may provide theflood elevations for the corresponding flood frequencies (e.g.,corresponding to the intersected flood frequency elevation surface). Asseen in FIG. 36 b, in some embodiments, two flood elevations atdifferent flood frequencies for the property point 3607 may be derivedfrom the flood-frequency elevation surfaces by using the elevationvalues at points, for example, where the first flood-frequency elevationsurface 3601 and the second flood-frequency elevation surface 3603 (suchas the 100 year flood elevation surface and the 500 year flood elevationsurface) intersect with the cross section surface 3605 that isperpendicular to the flood source (e.g., centerline 307) where theproperty point 3607 is located. For example, intersection point 3657 a(e.g., with elevation value of 198 m) between cross section 3605 and 500year flood elevation surface 3603 may provide the elevation value at thecorresponding 500 year flood frequency. Intersection point 3657 b (e.g.,with elevation value of 184 m) between cross section 3605 and 100 yearflood elevation surface 3601 may provide the elevation value at thecorresponding 100 year flood frequency. Intersecting lines among thesethree surfaces may provide flood elevation line features at differentflood frequencies. In some embodiments, the flood frequency elevationsurfaces may be generated based on elevation line features (e.g., BFEs)and a digital elevation map using a Triangulated Irregular Networkmethod (e.g., see FIG. 34). Other techniques for generating the floodfrequency elevation surfaces are also contemplated.

As shown in the sample flood water surface profile in FIG. 37, in someembodiments, points of flood frequency versus flood elevation for theproperty point may be derived from geo-referenced discrete points, onthe digital elevation map, for flood frequencies corresponding to alocation on the flood source in a flood water surface profile that is ona line substantially perpendicular to the flood source line feature andthe property point (e.g., line 1306 c in FIG. 13). In some embodiments,the flood water surface profile may provide flood elevation for a floodsource at given distances along the flood source (e.g., as determinedthrough an HH study). The flood water surface profile may be a floodprofile from a FEMA Flood Insurance Study developed by HH studies. Othersources of a flood water surface profile are also contemplated. In someembodiments, two flood elevations at different flood frequencies for theproperty point may be derived from point features or database records onthe geo-referenced discrete points from the flood water surface profile.The discrete points on a cross-section in the flood water surfaceprofile and the associated flood elevations may be geo-referenced andstored in a database. The database may also include additional discreteflood elevation points where a flood water surface meets the groundelevation of the digital elevation map. As shown in the sample floodwater surface profile in FIG. 37, multiple elevation points withdifferent flood frequencies at each cross section location may bedetermined. The flood elevation point database may be used to deriveflood elevations for the property point based on distances between twocloses elevation points to a cross section at the property point (e.g.,cross section indicated on the flood water surface profile for theproperty point). A collective database may be used in the floodelevation search for the property point. These points may also be usedas flood elevation versus flood frequency to generate a flood elevationversus flood frequency curve for the property point.

Embodiments of a subset or all (and portions or all) of the above may beimplemented by program instructions stored in a memory medium or carriermedium and executed by a processor. A memory medium may include any ofvarious types of memory devices or storage devices. The term “memorymedium” is intended to include an installation medium, e.g., a CompactDisc Read Only Memory (CD-ROM), floppy disks, or tape device; a computersystem memory or random access memory such as Dynamic Random AccessMemory (DRAM), Double Data Rate Random Access Memory (DDR RAM), StaticRandom Access Memory (SRAM), Extended Data Out Random Access Memory (EDORAM), Rambus Random Access Memory (RAM), etc.; or a non-volatile memorysuch as a magnetic media, e.g., a hard drive, or optical storage. Thememory medium may comprise other types of memory as well, orcombinations thereof. In addition, the memory medium may be located in afirst computer in which the programs are executed, or may be located ina second different computer that connects to the first computer over anetwork, such as the Internet. In the latter instance, the secondcomputer may provide program instructions to the first computer forexecution. The term “memory medium” may include two or more memorymediums that may reside in different locations, e.g., in differentcomputers that are connected over a network.

In some embodiments, a computer system at a respective participantlocation may include a memory medium(s) on which one or more computerprograms or software components according to one embodiment of thepresent invention may be stored. For example, the memory medium maystore one or more programs that are executable to perform the methodsdescribed herein. The memory medium may also store operating systemsoftware, as well as other software for operation of the computersystem.

In this patent, certain U.S. patents, U.S. patent applications, andother materials (e.g., articles) have been incorporated by reference.The text of such U.S. patents, U.S. patent applications, and othermaterials is, however, only incorporated by reference to the extent thatno conflict exists between such text and the other statements anddrawings set forth herein. In the event of such conflict, then any suchconflicting text in such incorporated by reference U.S. patents, U.S.patent applications, and other materials is specifically notincorporated by reference in this patent.

Further modifications and alternative embodiments of various aspects ofthe invention may be apparent to those skilled in the art in view ofthis description. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the invention. It is to beunderstood that the forms of the invention shown and described hereinare to be taken as embodiments. Elements and materials may besubstituted for those illustrated and described herein, parts andprocesses may be reversed, and certain features of the invention may beutilized independently, all as would be apparent to one skilled in theart after having the benefit of this description of the invention.Changes may be made in the elements described herein without departingfrom the spirit and scope of the invention as described in the followingclaims.

1. A computer-implemented method for predicting a flood elevation for aflood frequency for a property point, comprising: calculating with aprocessor at least two points of flood frequency versus flood elevationfor the property point using a flood map; defining a relationshipbetween flood frequency and flood elevation for the property point usingthe at least two points; and predicting with the processor at least oneflood elevation at a flood frequency different from the flood frequencyof one of the at least two points for the property point using therelationship; wherein the flood map comprises a map of flood zones,defined by flood boundaries, and a plurality of pre-existing floodelevation lines.
 2. A system, comprising: a processor; a memory coupledto the processor and configured to store program instructions executableby the processor to: calculate at least two points of flood frequencyversus flood elevation for the property point using a flood map; definea relationship between flood frequency and flood elevation for theproperty point using the at least two points; and predict at least oneflood elevation at a flood frequency different from the flood frequencyof one of the at least two points for the property point using therelationship; wherein the flood map comprises a map of flood zones,defined by flood boundaries, and a plurality of pre-existing floodelevation lines.
 3. A non-transitory computer-readable storage medium,comprising program instructions, wherein the program instructions arecomputer-executable to: calculate at least two points of flood frequencyversus flood elevation for the property point using a flood map; definea relationship between flood frequency and flood elevation for theproperty point using the at least two points; and predict at least oneflood elevation at a flood frequency different from the flood frequencyof one of the at least two points for the property point using therelationship; wherein the flood map comprises a map of flood zones,defined by flood boundaries, and a plurality of pre-existing floodelevation lines.